Copy source to target management in a data storage system

Copy source to target operations may be selectively and preemptively undertaken in advance of source destage operations. In another aspect, logic detects sequential writes including large block writes to point-in-time copy sources. In response, destage tasks on the associated point-in-time copy targets are started which include in one embodiment, stride-aligned copy source to target operations which copy unmodified data from the point-in-time copy sources to the point-in-time copy targets in alignment with the strides of the target. As a result, when write data of write operations is destaged to the point-in-time copy sources, such source destages do not need to wait for copy source to target operations since they have already been performed. In addition, the copy source to target operations may be stride-aligned with respect to the stride boundaries of the point-in-time copy targets. Other features and aspects may be realized, depending upon the particular application.

Preemptive staging for full-stride destage

There is a method for improving destage performance to a RAID array. The method periodically scans a cache for first strides that are ready to be destaged to a RAID array. While scanning the cache, the method identifies second strides that are not currently ready to be destaged to the RAID array, but will likely be ready to be destaged during a subsequent scan of the cache. The method initiates preemptive staging of any missing data of the second strides from the RAID array into the cache in preparation for the subsequent scan. Upon occurrence of the subsequent scan, the method destages, from the cache, the second strides from the cache to the RAID array.

WRITING ADJACENT TRACKS TO A STRIDE, BASED ON A COMPARISON OF A DESTAGING OF TRACKS TO A DEFRAGMENTATION OF THE STRIDE

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride.

Pinning content in nonvolatile memory

Systems and methods relating to pinning selected data to sectors in non-volatile memory. A graphical user interface allows a user to specify certain data (e.g., directories or files) to be pinned. A list of pinned sectors can be stored so that a driver or controller that operates on a sector basis and not a file or directory basis can identify data to be pinned.

Data storage and caching architecture

An extent record for an extent based data buffer that includes a host pointer that links the extent record to a next host extent record of a host extent record set, and a storage device pointer that links the extent record to a next storage device extent record of a storage device extent record set. Also, a system for transferring data between a host and a storage device that includes a data buffer coupled to the host and the storage device, where memory in the data buffer is divided into one or more extents, an extent table associated with the data buffer, where the extent table includes at least one extent record, an LBA chain table coupled to the host and the extent table, and a track section table coupled to the storage device and the extent table.

SECTOR-EDGE CACHE

Writing to storage disks using a differently sized sector format than that of the storage disk require sector edges to be read from sectors of the disks before awrite operation can occur. Write operations consequently incur a penalty by having to pre-read sector edges. A sector-edge cache avoids the performance penalty by storing sector edges obtained from the sectors during previously executed read and write operations. Rather than pre-reading a sector edge from disk during a write operation, an input/output controller can examine the sector-edge cache to determine if each appropriate sector edge is already present and then combine new data with that cached sector edge. RAID-5 implementations, which use a read-modify-write process to perform write operations, benefit from sector caches by reading and caching sector edges during the read phase so that no additional pre-reads are needed during the write phase.

CACHE MANAGEMENT METHOD AND CACHE DEVICE USING SECTOR SET

A cache management method and a cache device using a sector sets, are provided. The cache management method includes receiving at least one of a write request and a read request for predetermined data, from a host device. The cache determines whether a cache memory is allocated to a sector set including the predetermined sector, and selectively allocates the cache memory to the sector set based on the result of determination. The cache may store the data in the cache memory allocated to the sector set.

INTEGRATION OF APPLICATION INDICATED MINIMUM TIME TO CACHE TO LEAST RECENTLY USED TRACK DEMOTING SCHEMES IN A CACHE MANAGEMENT SYSTEM OF A STORAGE CONTROLLER

A minimum retention time in cache is indicated for a first plurality of tracks, where no minimum retention time is indicated for a second plurality of tracks. A cache management application demotes a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time.

Slice-based random access buffer for data interleaving

The disclosure is directed to a system and method for interleaving data utilizing a random access buffer that includes a plurality of independently accessible memory slots. The random access buffer is configured to store slices of incoming data sectors in free memory slots, where a free memory slot is identified by a status flag associated with a logical address of the free memory slot. Meanwhile, a label buffer is configured to store labels associated with the slices of the incoming data sectors in a sequence based upon an interleaving scheme. Media sectors including the interleaved data slices are read out from the memory slots of the random access buffer in order of the sequence of labels stored by the label buffer. As the media sectors are read out of the random access buffer, the corresponding memory slots are freed up for incoming slices of the next super-sector.

EFFICIENT PROCESSING OF CACHE SEGMENT WAITERS

Various embodiments for cache management in a distributed computing storage environment are provided. In one embodiment, a processor device, for a plurality of input/output (I/O) operations, initiates a process, separate from a process responsible for data segment assembly, for waking a predetermined number of waiting I/O operations. 1. A system for cache management in a distributed computing storage environment , the system comprising: 'for a plurality of input/output (I/O) operations, initiates a process, separate from a process responsible for data segment assembly, for waking a predetermined number of waiting I/O operations.', 'a processor device, operable in the computing storage environment, wherein the processor device2. The system of claim 1 , wherein the processor device initiates the process claim 1 , separate from a process responsible for the data segment assembly into the complete data tracks claim 1 , for waking a predetermined number of the I/O operations waiting to assemble complete data tracks from data segments.3. The system of claim 2 , wherein a total number of I/O operations to be awoken at each of an iterated instance of the waking is limited.4. The system of claim 2 , wherein the processor device removes claim 2 , pursuant to the waking process claim 2 , by a first I/O waiter claim 2 , the at least one complete data track off of a free list.5. The system of claim 4 , wherein the processor device performs the waking process for a first iteration subsequent to the data assembly process building at least one complete data track.6. The system of claim 5 , wherein the processor device wakes claim 5 , pursuant to the waking process claim 5 , if additional complete data tracks are available on the free list claim 5 , at least a second I/O waiter to remove the additional complete data tracks off the free list.7. The system of claim 6 , wherein the processor device iterates through at least one additional waking process corresponding to a predetermined ...

Using an access increment number to control a duration during which tracks remain in cache

Provided are a computer program product, system, and method for using an access increment number to control a duration during which tracks remain in cache. Tracks in a storage in the cache are indicated in a cache list. For each of the tracks indicated in the cache list, an access value is updated when one of the tracks is accessed in the cache. An access to a track in the cache indicated in the cache list is received. A determination is made as to whether an access increment number for the accessed track, wherein the access increment number is greater than one. The access value for the accessed track is incremented by the determined access increment number in response to the track being accessed in the cache. The access value for one of the tracks is used to determine whether to initiate to demote the track from the cache.

Invoking demote threads on processors to demote tracks indicated in demote ready lists from a cache when a number of free cache segments in the cache is below a free cache segment threshold

Provided are a computer program product, system, and method for invoking demote threads on processors to demote tracks from a cache. A plurality of demote ready lists indicate tracks eligible to demote from the cache. In response to determining that a number of free cache segments in the cache is below a free cache segment threshold, a determination is made of a number of demote threads to invoke on processors based on the number of free cache segments and the free cache segment threshold. The determined number of demote threads are invoked to demote tracks in the cache indicated in the demote ready lists, wherein each invoked demote thread processes one of the demote ready lists to select tracks to demote from the cache to free cache segments in the cache.

DATA STORAGE HIERARCHY AND ITS USE FOR DATA STORAGE SPACE MANAGEMENT

MANAGING I/O OPERATIONS FOR DATA OBJECTS IN A STORAGE SYSTEM

STORAGE SYSTEM AND ITS DATA PROCESSING METHOD

A cache memory is utilized effectively because data redundancy elimination is executed. A controller manages the cache memory by dividing it into a first area and a second area. When receiving a write access request from an access requestor, the controller divides a data block, which is an access target, into a plurality of chunks and searches the first area first and then the storage apparatus based on each chunk. If chunk storage information, indicating that each chunk is stored in the storage apparatus, does not exist in the first area or the storage apparatus, the controller executes chunk storage processing and creates and stores the chunk storage information. If the chunk storage information exists, the controller eliminates the chunk storage processing for storing the chunks. If the chunk storage information does not exist in the first area, the controller stages the chunk storage information from the storage apparatus to the first area on condition that the first area has an unused ...

Using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume

Provided are a computer program product, system, and method for using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume. A table includes a mirror indicator for each of a plurality of tracks in at least one data set in the primary volume indicating whether a track is to be mirrored to the secondary volume. In response to a write command of write data for one of the tracks in the primary volume, creating a record set in a cache for the primary volume including write data for the track to transfer to the secondary volume in response to the mirror indicator for the track indicating that the track is to be mirrored. The write data in the record set is transferred from the cache to the secondary volume.

Reducing overhead of managing cache areas

Maintaining multiple cache areas in a storage device having multiple processors includes loading data from a specific portion of non-volatile storage into a local cache slot in response to a specific processor of a first subset of the processors performing a read operation to the specific portion of non-volatile storage, where the local cache slot is accessible to the first subset of the processors and is inaccessible to a second subset of the processors that is different than the first subset of the processors and includes converting the local cache slot into a global cache slot in response to one of the processors performing a write operation to the specific portion of non-volatile storage, wherein the global cache area is accessible to the first subset of the processors and to the second subset of the processors. Different ones of the processors may be placed on different directors.

Using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache

Caching systems and methods for hard disk drives and hybrid drives

A system includes a read/write module and a caching module. The read/write module is configured to access a first portion of a recording surface of a rotating storage device. Data is stored on the first portion of the recording surface of the rotating storage device at a first density. The caching module is configured to cache data on a second portion of the recording surface of the rotating storage device at a second density. The second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device. The second density is less than the first density.

Adjustment of compression ratios for data storage

Storing data from a volatile memory of a host in a non-volatile memory (NVM) of a data storage device (DSD). Data from the volatile memory of the host is identified which has been compressed with a first compression ratio. The identified data is decompressed and a second compression ratio is determined based on a time to restore the data to the volatile memory of the host and characteristics of the NVM. At least a portion of the decompressed data is recompressed with the second compression ratio and at least a portion of the recompressed data is stored in the NVM.

Storage system

The provision of a technique by which, even when the data unit handled by a storage system controller and the data unit handled by a recording medium differ, the controller can perform input/output processing of data on the recording medium. The storage system comprises a disk controller for receiving write commands from a computer, and a plurality of disk devices in which data is written in accordance with the control of the disk controller. The size of the first block which constitutes the data unit handled in the execution of the input/output processing of the data in accordance with the write command by the disk controller and the size of the second block which constitutes the data unit handled in the execution of the input/output processing of data by the plurality of disk devices differ. The disk controller issues an instruction for the writing of data to the disk devices using a third block unit of a size corresponding to a common multiple of the size of the first block and the size ...

USING INSERTION POINTS TO DETERMINE LOCATIONS IN A CACHE LIST AT WHICH TO INDICATE TRACKS IN A SHARED CACHE ACCESSED BY A PLURALITY OF PROCESSORS

Provided are a computer program product, system, and method for using insertion points to determine locations in a cache list at which to indicate tracks in a shared cache accessed by a plurality of processors. A plurality of insertion points to a cache list for the shared cache having a least recently used (LRU) end and a most recently used (MRU) end identify tracks in the cache list. For each processor, of a plurality of processors, for which indication of tracks accessed by the processor is received, a determination is made of insertion points of the provided insertion points at which to indicate the tracks for which indication is received. The tracks are indicated at positions in the cache list with respect to the determined insertion points.

SMR drive that maintains physical locations of bands via flush/copy operations

When a shingled magnetic recording (SMR) hard disk drive (HDD) performs additional SMR band copy and/or flush operations to ensure that data associated with logical bands that are adjacent or proximate in logical space are stored in physical locations in the SMR HDD that are proximate in physical space. As a result, efficient execution is ensured of read commands that span multiple logical bands of the SMR HDD.

Using track locks and stride group locks to manage cache operations

Provided are a computer program product, system, and method for using track locks and stride group locks to manage cache operations. A group of tracks from the storage devices are stored in a cache. Exclusive track locks for tracks in the group in the cache are granted for writes to the tracks in the group in the cache, wherein exclusive track locks can be simultaneously held for writes to different tracks in the cache. An exclusive group lock for the group of tracks in the cache is granted to destage the tracks in the group from the cache to the storage devices. The exclusive group lock is released in response to completing the destage of the tracks in the group in the cache to the storage devices.

SECTOR-EDGE CACHE

Writing to storage disks using a differently sized sector format than that of the storage disk require sector edges to be read from sectors of the disks before awrite operation can occur. Write operations consequently incur a penalty by having to pre-read sector edges. A sector-edge cache avoids the performance penalty by storing sector edges obtained from the sectors during previously executed read and write operations. Rather than pre-reading a sector edge from disk during a write operation, an input/output controller can examine the sector-edge cache to determine if each appropriate sector edge is already present and then combine new data with that cached sector edge. RAID-5 implementations, which use a read-modify-write process to perform write operations, benefit from sector caches by reading and caching sector edges during the read phase so that no additional pre-reads are needed during the write phase.

INCREASED DESTAGING EFFICIENCY

Exemplary method, system, and computer program product embodiments for increased destaging efficiency by controlling destaging tasks to reduce long input/output (I/O) read operations in a computing environment are provided. In one embodiment, by way of example only destaging tasks are calculated according to one of a standard time interval and a variable recomputed destaging task interval. The destaging of storage tracks between a desired number of destaging tasks and a current number of destaging tasks is controlled according to the calculating. Additional system and computer program product embodiments are disclosed and provide related advantages.

Fast cache demotions in storage controllers with metadata

Provided are techniques for fast cache demotions in storage controllers with metadata. A track in a demotion structure is selected. In response to determining that the track in the demotion structure does not have invalidate metadata set, demoting the track from cache. In response to determining that the track has invalidate metadata set, the track is moved from the demotion structure to an invalidate metadata structure. One or more tasks are created to process the invalidate metadata structure, wherein each of the one or more tasks selects a different track in the invalidate metadata structure, invalidates metadata for that track, and demotes that track.

CONSIDERING A FREQUENCY OF ACCESS TO GROUPS OF TRACKS AND DENSITY OF THE GROUPS TO SELECT GROUPS OF TRACKS TO DESTAGE

Provided are a computer program product, system, and method for considering a frequency of access to groups of tracks and density of the groups to select groups of tracks to destage. One of a plurality of densities for one of a plurality of groups of tracks is incremented in response to determining at least one of that the group is not ready to destage and that one of the tracks in the group in the cache transitions to being ready to destage. A determination is made of a group frequency indicating a frequency at which tracks in the group are modified. At least one of the density and the group frequency is used for each of the groups to determine whether to destage the group. The tracks in the group in the cache are destaged to the storage in response to determining to destage the group.

DETERMINING MODIFIED TRACKS TO DESTAGE DURING A CACHE SCAN

Provided are a computer program product, system, and method for determining modified tracks to destage during a cache scan. A cache scan is initiated at a time interval to determine modified tracks to destage from a cache to the first or second storage. A modified track is processed during the cache scan. The modified track is destaged to the first storage in response to the modified track stored in the first storage. A determination is made as to whether there was a host write to the second storage since a previous cache scan in response to the modified track stored in the second storage. The modified track is destaged to the second storage in response to determining that there was a host write to the second storage since the previous cache scan.

Using a machine learning module to perform destages of tracks with holes in a storage system

In response to an end of track access for a track in a cache, a determination is made as to whether the track has modified data and whether the track has one or more holes. In response to determining that the track has modified data and the track has one or more holes, an input on a plurality of attributes of a computing environment in which the track is processed is provided to a machine learning module to produce an output value. A determination is made as to whether the output value indicates whether one or more holes are to be filled in the track. In response to determining that the output value indicates that one or more holes are to be filled in the track, the track is staged to the cache from a storage drive.

Journey data re-evaluation

Methods, systems, and computer program products for processing a transaction request associated with a travel record, where the travel record includes at least one previously booked segment. The transaction request may be received at an inventory system, where the transaction request identifies at least one requested segment for the travel record. The inventory system analyzes the at least one previously-booked segment of the travel record and the at least one requested segment of the transaction request to identify at least one particular previously booked segment as a candidate for re-evaluation segment based at least in part on whether the at least one particular previously-booked segment and the at least one requested segment correspond to a particular journey. Availability may be computed for the at least one requested segment and the at least one candidate for re-evaluation segment, and a sell decision may be generated based at least partially on the computed availability. 104 RESERVATION RESERVATION NETWORK SYSTEM /4 INVENTORY SYSTEMS)

JOURNEY DATA RE-EVALUATION

Methods, systems, and computer program products for processing a transaction request associated with a travel record, where the travel record includes at least one previously-booked segment. The transaction request may be received at an inventory system, where the transaction request identifies at least one requested segment for the travel record. The inventory system analyzes the at least one previously-booked segment of the travel record and the at least one requested segment of the transaction request to identify at least one particular previously-booked segment as a candidate for re-evaluation segment based at least in part on whether the at least one particular previously-booked segment and the at least one requested segment correspond to a particular journey. Availability may be computed for the at least one requested segment and the at least one candidate for re-evaluation segment, and a sell decision may be generated based at least partially on the computed availability.

Caching systems and methods for hard disk drives and hybrid drives

POPULATING A SECOND CACHE WITH TRACKS FROM A FIRST CACHE WHEN TRANSFERRING MANAGEMENT OF THE TRACKS FROM A FIRST NODE TO A SECOND NODE

Provided are a computer program product, system, and method for populating a second cache with tracks from a first cache when transferring management of the tracks from a first node to a second node. Management of a first group of tracks in the storage managed by the first node is transferred to the second node managing access to a second group of tracks in the storage. After the transferring the management of the tracks, the second node manages access to the first and second groups of tracks and caches accessed tracks from the first and second groups in the second cache of the second node. The second cache of the second node is populated with the tracks in a first cache of the first node ...

Integration of secure data transfer applications for generic IO devices

Techniques are presented for sending an application instruction from a hosting digital appliance to a portable medium, where the instruction is structured as one or more units whose size is a first size, or number of bytes. After flushing the contents of a cache, the instruction is written to the cache, where the cache is structured as logical blocks having a size that is a second size that is larger (in terms of number of bytes) than the first size. In writing the instruction (having a command part and, possibly, a data part), the start of the instruction is aligned with one of the logical block boundaries in the cache and the instruction is padded out with dummy data so that it fills an integral number of the cache blocks. When a response from a portable device to an instruction is received at a hosting digital appliance, the cache is similarly flushed prior to receiving the response. The response is then stored to align with a logical block boundary of the cache.

Using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache

Provided are a computer program product, system, and method for using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache. A track format table associates track format codes with track format metadata. A determination is made as to whether the track format table has track format metadata matching track format metadata of a track staged into the cache. A determination is made as to whether a track format code from the track format table for the track format metadata in the track format table matches the track format metadata of the track staged. A cache control block for the track being added to the cache is generated including the determined track format code when the track format table has the matching track format metadata.

Efficient processing of cache segment waiters

For a plurality of input/output (I/O) operations waiting to assemble complete data tracks from data segments, a process, separate from a process responsible for the data assembly into the complete data tracks is initiated, and the at least one complete data track is removed off of a free list by a first I/O waiter.

Populating a first stride of tracks from a first cache to write to a second stride in a second cache

Provided are a computer program product, system, and method for managing data in a cache system comprising a first cache, a second cache, and a storage system. A determination is made of tracks stored in the storage system to demote from the first cache. A first stride is formed including the determined tracks to demote. A determination is made of a second stride in the second cache in which to include the tracks in the first stride. The tracks from the first stride are added to the second stride in the second cache. A determination is made of tracks in strides in the second cache to demote from the second cache. The determined tracks to demote from the second cache are demoted.

Copy source to target management in a data storage system

Copy source to target management in a data storage system

Permutation apparatus, permutation method, and program

The present invention performs a replacement process at high speed. An element count determination unit (22) calculates the number of elements included in each allocation destination. A start position determination (23) calculates a start position that corresponds to each allocation destination. An allocation destination determination unit (24) calculates a row of values that represent allocation destinations in a buffer. A replacement generation unit (25) calculates a row of values that represent replacement destinations within each allocation destination. An initial position setting unit (31) sets the start position of a value indicating the position being processed that corresponds to each allocation destination. A rearrangement unit (32) sets the elements of a vector to each allocation destination of the buffer. A replacement execution unit (33) executes a discretionary reverse replacement algorithm for each allocation destination and thereby generates an output vector.

Adjusting insertion points used to determine locations in a cache list at which to indicate tracks based on number of tracks added at insertion points

Provide a computer program product, system, and method for adjusting insertion points used to determine locations in a cache list at which to indicate tracks based on number of tracks added at insertion points. There are a plurality of insertion points to a cache list for the cache having a least recently used (LRU) end and a most recently used (MRU) end. Each insertion point of the insertion points identifies a track in the cache list. A plurality of tracks are indicated at positions in the cache list with respect to insertion points. For each track indicated at an insertion point of the insertion points, at least one insertion point counter for at least one insertion point with respect to the insertion point at which the track is indicated is incremented. A plurality of the insertion points are adjusted to point to different tracks in the cache list based on insertion point counters for the insertion points.

Invalidating CKD data tracks prior to unpinning, wherein upon destaging invalid track image from cache to a track of data on storage drive, the track of data on the storage drive is unpinned which enables destages of data from the cache to the track of data on the storage drive going forward

A method for invalidating a track of data on a storage drive in preparation to unpin the track is disclosed. In one embodiment, such a method includes invalidating certain metadata associated with a track of data residing on a storage drive of a storage system. The method further creates, in cache of the storage system, an invalid track image associated with the track. The method destages, from the cache, the invalid track image to the storage drive. Once the invalid track image is destaged, the method may unpin the track in cache, thereby enabling destages of the track from the cache to the storage drive going forward. A corresponding system and computer program product are also disclosed.

Using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache

Integration of Secure Data Transfer Applications for Generic IO Devices

Techniques are presented for sending an application instruction from a hosting digital appliance to a portable medium, where the instruction is structured as one or more units whose size is a first size, or number of bytes. After flushing the contents of a cache, the instruction is written to the cache, where the cache is structured as logical blocks having a size that is a second size that is larger (in terms of number of bytes) than the first size. In writing the instruction (having a command part and, possibly, a data part), the start of the instruction is aligned with one of the logical block boundaries in the cache and the instruction is padded out with dummy data so that it fills an integral number of the cache blocks. When a response from a portable device to an instruction is received at a hosting digital appliance, the cache is similarly flushed prior to receiving the response. The response is then stored to align with a logical block boundary of the cache.

Determining modified tracks to destage during a cache scan

Provided are a computer program product, system, and method for determining modified tracks to destage during a cache scan. A cache scan is initiated at a time interval to determine modified tracks to destage from a cache to the first or second storage. A modified track is processed during the cache scan. The modified track is destaged to the first storage in response to the modified track stored in the first storage. A determination is made as to whether there was a host write to the second storage since a previous cache scan in response to the modified track stored in the second storage. The modified track is destaged to the second storage in response to determining that there was a host write to the second storage since the previous cache scan.

Using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache

Provided are a computer program product; system, and method for using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache. A track format table associates track format codes with track format metadata. A determination is made as to whether the track format table has track format metadata matching track format metadata of a track staged into the cache. A determination is made as to whether a track format code from the track format table for the track format metadata in the track format table matches the track format metadata of the track staged. A cache control block for the track being added to the cache is generated including the determined track format code when the track format table has the matching track format metadata.

EFFICIENT CACHE VOLUME SIT SCANS

A processor, operable in a computing storage environment, allocates portions of a Scatter Index Table (SIT) disproportionately between a larger portion dedicated for meta data tracks, and a smaller portion dedicated for user data tracks, and processes a storage operation through the disproportionately allocated portions of the SIT using an allocated number of Task Control Blocks (TCB).

INVALIDATING TRACK FORMAT INFORMATION FOR TRACKS IN CACHE

Provided are a computer program product, system, and method for invalidating track format information for tracks in cache. Demoted tracks demoted from the cache are indicated in a demoted track list. Track format information is saved for the demoted tracks. The track format information indicates a layout of data in the demoted tracks, wherein the track format information for the demoted tracks is used when the demoted tracks are staged back into the cache. An operation is initiated to invalidate a metadata track of the metadata tracks in the storage. Demoted tracks indicated in the demoted track list having metadata in the metadata track to invalidate are removed. The track format information for the demoted tracks having metadata in the metadata track to invalidate is removed. 1. A computer program product for managing metadata on tracks in a storage cached in a cache , the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that is executable to perform operations , the operations comprising:maintaining, in the storage, metadata tracks, wherein each metadata track of the metadata tracks has metadata for multiple of the tracks in the storage;maintaining a track format table associating track format codes with different track format metadata, wherein each instance of the track format metadata in the track format table indicates a layout of data in a track;maintaining cache control blocks for tracks in the cache, wherein each cache control block of the cache control blocks includes a track format code comprising one of the track format codes in the track format table indicating a layout of data in the track in the cache;initiating an operation to invalidate a metadata track of the metadata tracks in the storage;determining tracks having metadata in the metadata track to invalidate;determining cache control blocks for the determined tracks that are in the cache; andindicating the track format ...

Obtaining cache resources for expected writes to tracks in write set after the cache resources were released for the tracks in the write set

Provided are a computer program product, system, and method for prefetching cache resources for a write request from a host to tracks in storage cached in a cache. Cache resources held for a plurality of tracks in a write set are released before expected writes are received for the tracks in the write set. Cache resources for tracks in the write set are obtained, following the release of the cache resources, to use for expected write requests to the tracks in the write set.

Obtaining cache resources for expected writes to tracks in write set after the cache resources were released for the tracks in the write set

SHINGLED MAGNETIC RECORDING STORAGE SYSTEM

Methods and systems that reduce off-track write retry operations in shingled magnetic recording systems. In one implementation, the method includes writing data to an initial track, determining which side of the initial track is a shingled side, calculating a percentage of position error signal (PES) at a shingled side end of the initial track (PES1) when an off-track write operation occurs, determining whether the PES1 meets a first pre-determined threshold, continue writing data to a second track responsive to determining the PES1 is below a first pre-determined threshold, calculating a percentage of PES at a shingled side end of the second track (PES2), determining whether a combined value of PES1 and PES2 is above a second predetermined threshold to determine a probability value of the initial track being erased, and continue writing to a third track if the combined value is below the second predetermined threshold. 1. A method comprising:receiving a write command to write data on an initial track in a band of a shingled magnetic recording medium;calculating a percentage of position error signal (PES) of the initial track (PES1);determining a relationship of the percentage of PES1 to a first pre-determined threshold;responsive to the percentage of PES1 being above the first pre-determined threshold, re-writing the data to the initial track or to a media cache; andresponsive to the percentage of PES1 being below the first pre-determined threshold, writing the data to a second track adjacent the initial track.2. The method of claim 1 , responsive to writing the data to the second track claim 1 , further comprising:calculating a percentage of PES of the second track (PES2); anddetermining whether a combined value of percentage of PES1 and percentage of PES2 is above a second pre-determined threshold.3. The method of claim 2 , further comprising:re-writing the data to the initial track responsive to determining the combined value of percentage of PES1 and percentage ...

Handling cache and non-volatile storage (NVS) out of sync writes

Provided are techniques for handling cache and Non-Volatile Storage (NVS) out of sync writes. At an end of a write for a cache track of a cache node, a cache node uses cache write statistics for the cache track of the cache node and Non-Volatile Storage (NVS) write statistics for a corresponding NVS track of an NVS node to determine that writes to the cache track and to the corresponding NVS track are out of sync. The cache node sets an out of sync indicator in a cache data control block for the cache track. The cache node sends a message to the NVS node to set an out of sync indicator in an NVS data control block for the corresponding NVS track. The cache node sets the cache track as pinned non-retryable due to the write being out of sync and reports possible data loss to error logs.

Host mapping logical storage devices to physical storage devices

A host system may include metadata mapping logical storage devices and logical addresses therein to physical storage devices and physical addresses therein. For a read operation, the host system, if it is determined that the data is not in cache on the storage system, the host system may determine, from the device-mapping metadata, the physical storage device and physical location (e.g., address range) therein of the data to be read. The data then may be read from the physical storage device over the internal fabric of the storage system without use of a director. Data may be read from the physical storage device to the host system using RDMA communications that do not involve use of any CPU resources on the host system or the storage system.

Maintaining cache hit ratios for insertion points into a cache list to optimize memory allocation to a cache

Provided are a computer program product, system, and method for maintaining cache hit ratios for insertion points into a cache list to optimize memory allocation to a cache. A plurality of insertion points to a cache list for the cache each identify a track in the cache list. Insertion points to tracks in the cache list are used to determine locations in the cache list at which to indicate tracks in the cache in the cache list that are to be indicated at the MRU end of the cache list. Indication is made of cache hits for each of the insertion points used to indicate locations in the cache list for tracks accessed while indicated in the cache list. The cache hits indicated for the insertion points are to indicate whether to increase or decrease a size of the cache.

Using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache

Provided are a computer program product, system, and method for using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache. A track format table associates track format codes with track format metadata. A determination is made as to whether the track format table has track format metadata matching track format metadata of a track staged into the cache. A determination is made as to whether a track format code from the track format table for the track format metadata in the track format table matches the track format metadata of the track staged. A cache control block for the track being added to the cache is generated including the determined track format code when the track format table has the matching track format metadata.

Replacement device, replacement method, and program

The present invention performs a replacement process at high speed. An element count determination unit (22) calculates the number of elements included in each allocation destination. A start position determination (23) calculates a start position that corresponds to each allocation destination. An allocation destination determination unit (24) calculates a row of values that represent allocation destinations in a buffer. A replacement generation unit (25) calculates a row of values that represent replacement destinations within each allocation destination. An initial position setting unit (31) sets the start position of a value indicating the position being processed that corresponds to each allocation destination. A rearrangement unit (32) sets the elements of a vector to each allocation destination of the buffer. A replacement execution unit (33) executes a discretionary reverse replacement algorithm for each allocation destination and thereby generates an output vector.

ALLOCATION OF CACHE STORAGE AMONG APPLICATIONS BASED ON APPLICATION PRIORITY AND MINIMUM RETENTION TIME FOR TRACKS IN LEAST RECENTLY USED DEMOTING SCHEMES

A computational device receives an indication of minimum retention times in a cache for a plurality of tracks for applications. In response to determining that a first type of application has not specified a maximum percentage of cache for allocation to the first type of application, the maximum percentage of cache for allocation to the first type of application is set to a default value. In response to determining that a second type of application has not specified a maximum percentage of cache for allocation to the second type of application, an entirety of the cache or a percentage of the cache that is greater than the default value is allocated for the second type of application. A least recently used based replacement of tracks is performed in the cache while attempting to satisfy the minimum retention times and the maximum percentage of cache that are allocated. 1. A method , comprising:receiving, by a computational device, an indication of minimum retention times in a cache for a plurality of tracks of a plurality of applications;in response to determining that a first type of application has not specified a maximum percentage of cache for allocation to the first type of application, setting the maximum percentage of cache for allocation to the first type of application to a default value; andin response to determining that a second type of application has not specified a maximum percentage of cache for allocation to the second type of application, allowing an entirety of the cache or a higher percentage of the cache that is greater than the default value to be allocated for the second type of application; andperforming least recently used (LRU) based replacement of tracks in the cache while attempting to satisfy the minimum retention times and the maximum percentage of cache that are allocated for the plurality of applications.2. The method of claim 1 , wherein the second type of application includes at least one of an operating system claim 1 , a device ...

METHOD AND SYSTEM FOR EFFICIENTLY EVICTING DATA FROM MEMORY SLOTS IN A STORAGE SYSTEM

A method for managing data includes generating, by an offload device, predicted active logical partition data using an active logical partition mapping obtained from a host computing device, generating logical partition correlation data using active memory track maps obtained from the host computing device, generating most probable tracks using the predicted active logical partition data and the logical partition correlation data, and sending the most probable tracks to the host computing device, wherein the host computing device evicts data from a memory device based on the most probable tracks.

SECTOR-EDGE CACHE

Software that writes to storage disks using a differently sized sector format than that of the storage disks can require sector edges to be read from sectors of the disks before the write operation can occur. Write operations can consequently incur a performance penalty by having to pre-read sector edges. A sector-edge cache avoids this performance penalty by storing sector edges obtained from the sectors during previously executed read and write operations. Instead of having to pre-read a sector edge from disk during a write operation, an input/output controller can examine the sector-edge cache to determine if each appropriate sector edge is already present and then combine new data with that cached sector edge. RAID-5 implementations, which use a read-modify-write process to perform write operations, benefit from sector caches by reading and caching sector edges during the read phase so that no additional pre-reads are needed during the write phase.

CACHING SYSTEMS AND METHODS FOR HARD DISK DRIVES AND HYBRID DRIVES

A system includes a read/write module and a caching module. The read/write module is configured to access a first portion of a recording surface of a rotating storage device. Data is stored on the first portion of the recording surface of the rotating storage device at a first density. The caching module is configured to cache data on a second portion of the recording surface of the rotating storage device at a second density. The second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device. The second density is less than the first density.

EFFICIENT METADATA DESTAGE DURING SAFE DATA COMMIT OPERATION

A method for reducing I/O performance impacts associated with a data commit operation is disclosed. In one embodiment, such a method includes periodically performing a data commit operation wherein modified data is destaged from cache to persistent storage drives. Upon performing a particular instance of the data commit operation, the method determines whether modified data in the cache is a metadata track. In the event the modified data is a metadata track, the method attempts to acquire an exclusive lock on the metadata track. In the event the exclusive lock cannot be acquired, the method skips over the metadata track without destaging the metadata track for the particular instance of the data commit operation. A corresponding system and computer program product are also disclosed.

Using track locks and stride group locks to manage cache operations

Using track locks and stride group locks to manage cache operations

Providing track access reasons for track accesses resulting in release of prefetched cache resources for track

Provided are a computer program product, system, and method for providing track access reasons for track accesses resulting in the release of prefetched cache resources for the track. A first request for a track is received from a process for which prefetched cache resources to a cache are held for a second request for the track that is expected. A track access reason is provided for the first request specifying a reason for the first request. The prefetched cache resources are released before the second request to the track is received. Indication is made in an unexpected released track list of the track and the track access reason for the first request.

To increase the efficiency of the degradation of the

Storage system

在存储系统的控制部处理的数据单位和记录媒体处理的数据单位不同时，探求用于使其控制部也能进行向记录媒体的数据输入输出处理的技术。存储系统，具有从计算机接收写命令的磁盘控制器和根据磁盘控制器的控制写入数据的多个磁盘装置。在磁盘控制器根据写命令实行数据的输入输出处理时作为处理数据单位的第一块的尺寸、和在多个磁盘装置的各个实行数据输入输出处理时作为处理数据单位的第二块的尺寸不同。而且，磁盘控制器用具有第一块的尺寸和第二块的尺寸的公倍数的尺寸的第三块单位，对磁盘装置指示数据的写入。

Populating a second cache with tracks from a first cache when transferring management of the tracks from a first node to a second node

Provided are a computer program product, system, and method for populating a second cache with tracks from a first cache when transferring management of the tracks from a first node to a second node. Management of a first group of tracks in the storage managed by the first node is transferred to the second node managing access to a second group of tracks in the storage. After the transferring the management of the tracks, the second node manages access to the first and second groups of tracks and caches accessed tracks from the first and second groups in the second cache of the second node. The second cache of the second node is populated with the tracks in a first cache of the first node.

Integration of application indicated maximum time to cache to least recently used track demoting schemes in a cache management system of a storage controller

A computational device receives an indication that specifies a maximum retention time in cache for a first plurality of tracks, wherein no maximum retention time is specified for a second plurality of tracks. A plurality of insertions points are generated in a least recently used (LRU) list, wherein different insertion points in the LRU list correspond to different amounts of time that a track of the first plurality of tracks is expected to be retained in the cache, wherein the LRU list is configured to demote both tracks of the first plurality of tracks and the second plurality of tracks from the cache.

HOST CACHE COHERENCY WHEN READING DATA

When a read request for the data portion is received from an application executing on a host, the host may determine whether the data portion is in host cache, and if so, whether the logical storage unit of the data portion is shared by another host system. If there is another host system sharing the logical storage unit, a latest version stored on the storage system may be determined and compared to the version stored in the host cache. If the version in the host cache is the same as the latest version stored on the storage system, the data portion may be retrieved from the host cache. If the version in the host cache is not the latest version stored on the storage system, the data portion may be retrieved from the storage system, and the host cache may be updated with the latest version of the data portion.

Using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume

Provided are a computer program product, system, and method for using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume. A table includes a mirror indicator for each of a plurality of tracks in at least one data set in the primary volume indicating whether a track is to be mirrored to the secondary volume. In response to a write command of write data for one of the tracks in the primary volume, creating a record set in a cache for the primary volume including write data for the track to transfer to the secondary volume in response to the mirror indicator for the track indicating that the track is to be mirrored. The write data in the record set is transferred from the cache to the secondary volume.

EFFICIENT CACHE VOLUME SIT SCANS

A processor, operable in a computing storage environment, allocates portions of a Scatter Index Table (SIT) disproportionately between a larger portion dedicated for meta data tracks, and a smaller portion dedicated for user data tracks, and processes a storage operation through the disproportionately allocated portions of the SIT using an allocated number of Task Control Blocks (TCB).

TAPE DRIVE WITH INTELLIGENT SELECTION OF WRAP / TRACK FOR TEMPORARILY STORING FLUSHED DATA

A tape drive that can select one or more wraps from any available wraps on a tape medium for writing temporary data upon detecting a flush condition. The one or more wraps selected for writing temporary data can be selected from wraps otherwise reserved for normal writing operations. Selection of the one or more wraps for temporary writing may be based on multiple considerations, including proximity to the wrap of current data writing operations and tape medium degradation. The one or more wraps selected for writing temporary data may be selected with or without regard of their assigned read/write direction. Assigning wraps based on proximity and/or degradation can lead to certain operational advantages including reducing tape write head movement in the transverse direction and spreading tape medium wear more evenly across the surface of the tape medium.

Managing read requests from multiple requestors

Techniques are disclosed for managing data requests from multiple requestors. According to one implementation, when a new data request is received, a determination is made as to whether a companion relationship should be established between the new data request and an existing data request. Such a companion relationship may be appropriate under certain conditions. If a companion relationship is established between the new data request and an existing data request, then when data is returned for one request, it is used to satisfy the other request as well. This helps to reduce the number of data accesses that need to be made to a data storage, which in turn enables system efficiency to be improved.

Writing adjacent tracks to a stride, based on a comparison of a destaging of tracks to a defragmentation of the stride

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride.

PINNING CONTENT IN NONVOLATILE MEMORY

Systems and methods relating to pinning selected data to sectors in non-volatile memory. A graphical user interface allows a user to specify certain data (e.g., directories or files) to be pinned. A list of pinned sectors can be stored so that a driver or controller that operates on a sector basis and not a file or directory basis can identify data to be pinned.

Allocation of cache storage among applications based on application priority and minimum retention time for tracks in least recently used demoting schemes

A computational device receives an indication of minimum retention times in a cache for a plurality of tracks for applications. In response to determining that a first type of application has not specified a maximum percentage of cache for allocation to the first type of application, the maximum percentage of cache for allocation to the first type of application is set to a default value. In response to determining that a second type of application has not specified a maximum percentage of cache for allocation to the second type of application, an entirety of the cache or a percentage of the cache that is greater than the default value is allocated for the second type of application. A least recently used based replacement of tracks is performed in the cache while attempting to satisfy the minimum retention times and the maximum percentage of cache that are allocated.

Destaging of write ahead data set tracks

Exemplary methods, computer systems, and computer program products for efficient destaging of a write ahead data set (WADS) track in a volume of a computing storage environment are provided. In one embodiment, the computer environment is configured for preventing destage of a plurality of tracks in cache selected for writing to a storage device. For a track N in a stride Z of the selected plurality of tracks, if the track N is a first WADS track in the stride Z, clearing at least one temporal bit for each track in the cache for the stride Z minus 2 (Z2), and if the track N is a sequential track, clearing the at least one temporal bit for the track N minus a variable X (NX).

STORAGE SYSTEM AND STORING METHOD

Processing read and write requests for tracks in a cache using track format codes in a cache control block of a track in a cache

System and method for storing data sectors with header and trailer information in a disk cache supporting memory compression

A computing system includes a storage server having a memory organization that includes a compressed memory device for storing sectors, each sector having a sector data portion and associated header and trailers, either attached by the hosts or by components of the computing system. The compressed memory device comprises a memory directory and a plurality of fixed-size blocks. The system implements a methodology for detaching headers and trailers from sectors before storing the sectors in the memory, and storing the headers and trailers in the memory disk cache, separate from the sector data portion; and, reattaching headers and trailers to sector data portions when the sectors are sent from the memory to a host or to a mass storage device. The header and trailer data are managed through the same memory directory used to manage the compressed main memory. The process of detaching headers and trailers from sectors for separate storage results in increased efficacy of data compression, thus yielding better compression ratios, and decreased memory traffic generated by host reads, host writes, cache stages and cache destages.

TRANSFER TRACK FORMAT INFORMATION FOR TRACKS IN CACHE AT A PRIMARY STORAGE SYSTEM TO A SECONDARY STORAGE SYSTEM TO WHICH TRACKS ARE MIRRORED TO USE AFTER A FAILOVER OR FAILBACK

Provided are a computer program product, system, and method to transfer track format information for tracks in cache at a primary storage system to a secondary storage system to which tracks are mirrored to use after a failover or failback. In response to a failover from the primary storage system to the secondary storage system, the primary storage system adds a track identifier of the track and track format information indicating a layout of data in the track, indicated in track metadata for the track in the primary storage, to a cache transfer list. The primary storage system transfers the cache transfer list to the secondary storage system to use the track format information in the cache transfer list for a track staged into the secondary cache having a track identifier in the cache transfer list. 123-. (canceled)24. A computer program product for performing a failover from a primary storage system having a primary cache and a primary storage to a secondary storage system having a secondary cache and a secondary storage , the computer program product comprising a computer readable storage medium having computer readable program code executed in the primary storage system to perform operations , the operations comprising:in response to failover from the primary storage system to the secondary storage system, for each track in the primary cache, adding a track identifier of the track and track format information indicating metadata of the track, including a layout of data in the track, to a cache transfer list; andtransferring the cache transfer list to the secondary storage system to cause the secondary storage system to use the track format information transferred with the cache transfer list for a track staged into the secondary cache from the secondary storage having a track identifier in the cache transfer list after the failover.25. The computer program product of claim 24 , wherein prior to the failover while the primary storage system comprises an active ...

VERWENDEN VON SPURSPERREN UND SCHRITTWEITENGRUPPENSPERREN ZUM VERWALTEN VON CACHEOPERATIONEN

Es wird ein Computerprogrammprodukt, System und Verfahren bereitgestellt, um mittels Spursperren und Schrittweitengruppensperren Cacheoperationen zu verwalten. Eine Gruppe von Spuren von den Speichereinheiten wird in einem Cache gespeichert. Exklusive Spursperren für Spuren in der Gruppe im Cache werden für Schreibvorgänge auf die Spuren in der Gruppe im Cache gewährt, wobei exklusive Spursperren gleichzeitig für Schreibvorgänge auf verschiedene Spuren im Cache vorgehalten werden können. Eine exklusive Gruppensperre für die Gruppe von Spuren im Cache wird gewährt, um die Spuren in der Gruppe aus dem Cache in die Speichereinheiten auszulagern. Die exklusive Gruppensperre wird aufgehoben, wenn das Auslagern der Spuren in der Gruppe im Cache in die Speichereinheiten ausgeführt ist.

Increased destaging efficiency for smoothing of destage tasks based on speed of disk drives

For increased destaging efficiency by smoothing destaging tasks to reduce long input/output (I/O) read operations in a computing environment, the ramp up of the destaging tasks is adjusted based on speed of disk drives when smoothing the destaging of storage tracks between a desired number of destaging tasks and a current number of destaging tasks by calculating destaging tasks according to one of a standard time interval and a variable recomputed destaging task interval.

Using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume

Provided are a computer program product, system, and method for using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume. A table includes a mirror indicator for each of a plurality of tracks in at least one data set in the primary volume indicating whether a track is to be mirrored to the secondary volume. In response to a write command of write data for one of the tracks in the primary volume, creating a record set in a cache for the primary volume including write data for the track to transfer to the secondary volume in response to the mirror indicator for the track indicating that the track is to be mirrored. The write data in the record set is transferred from the cache to the secondary volume.

Sector management in drives having multiple modulation coding

Systems and methods are disclosed for implementing sector management in drives having multiple modulation coding. A circuit may be configured to generate a data sector having a first number of bits based on a first modulation encoding scheme associated with a first location of a data storage medium, determine a difference between the first number of bits and a second number of bits corresponding to a second modulation encoding scheme associated with a second location of the data storage medium, append a number of padding bits to the data sector based on the difference, and store the data sector to the second location of the data storage medium. The data sector may be a sector reallocated from the first location to the second location. The data sector may also be an intermediate parity sector stored to a media cache region of the data storage device.

FILE ACCESS PREDICATION USING COUNTER BASED EVICTION POLICIES AT THE FILE AND PAGE LEVEL

The disclosure relates to technology for predicting file access patterns by identifying one or more files stored in a first cache and one or more pages associated with each of the one or more files in a second cache. The one or more files in the first cache are evicted based on a first eviction policy and, for each of the one or more files, the one or more pages in the second cache are evicted based on a second eviction policy. Access patterns of the one or more files based on the first and second eviction policies may then be predicted.

Efficient cache volume sit scans

A processor, operable in a computing storage environment, allocates portions of a Scatter Index Table (SIT) disproportionately between a larger portion dedicated for meta data tracks, and a smaller portion dedicated for user data tracks, and processes a storage operation through the disproportionately allocated portions of the SIT using an allocated number of Task Control Blocks (TCB).

Writing adjacent tracks to a stride, based on a comparison of a destaging of tracks to a defragmentation of the stride

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride.

Höhere Auslagerungseffizienz

Beispielhafte Ausführungsformen von einem Verfahren, einem System und einem Computer-Programmprodukt für eine höhere Auslagerungseffizienz, indem Auslagerungstasks gesteuert werden, um lange Eingabe-/Ausgabe-(E/A-)Leseoperationen in einer Datenverarbeitungsumgebung zu verkürzen, werden bereitgestellt. In einer Ausführungsform werden beispielhalber nur Auslagerungstasks entweder gemäß einem Standard-Zeitintervall oder gemäß einem veränderlichen, neu berechneten Auslagerungstask-Intervall berechnet. Die Auslagerung von Speicher-Tracks zwischen einer gewünschten Anzahl von Auslagerungstasks und einer aktuellen Anzahl von Auslagerungstasks wird entsprechend der Berechnung gesteuert. Zusätzliche Ausführungsformen von Systemen und Computer-Programmprodukten werden offenbart und bieten mit ihnen verbundene Vorteile.

INTEGRATION OF SECURE DATA TRANSFER APPLICATIONS FOR GENERIC IO DEVICES

CACHING SYSTEMS AND METHODS FOR HARD DISK DRIVES AND HYBRID DRIVES

A system includes a read/write module and a caching module. The read/write module is configured to access a first portion of a recording surface of a rotating storage device. Data is stored on the first portion of the recording surface of the rotating storage device at a first density. The caching module is configured to cache data on a second portion of the recording surface of the rotating storage device at a second density. The second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device. The second density is less than the first density.

Hard disk drive with attached solid state drive cache

Methods, systems, and computer programs for managing storage using a solid state drive (SSD) read cache memory are presented. One method includes an operation for determining whether data corresponding to a read request is available in a SSD memory when the read request causes a miss in a memory cache. The read request is served from the SSD memory when the data is available in the SSD memory, and when the data is not available in the SSD memory, SSD memory tracking logic is invoked and the read request is served from a hard disk drive. Invoking the SSD memory tracking logic includes determining whether a fetch criteria for the data has been met, and loading the data corresponding to the read request in the SSD memory when the fetch criteria has been met. The use of the SSD as a read cache improves memory performance for random data reads.

STORAGE SYSTEM AND ITS DATA PROCESSING METHOD

A cache memory is utilized effectively because data redundancy elimination is executed. A controller manages the cache memory by dividing it into a first area and a second area. When receiving a write access request from an access requestor, the controller divides a data block, which is an access target, into a plurality of chunks and searches the first area first and then the storage apparatus based on each chunk. If chunk storage information, indicating that each chunk is stored in the storage apparatus, does not exist in the first area or the storage apparatus, the controller executes chunk storage processing and creates and stores the chunk storage information. If the chunk storage information exists, the controller eliminates the chunk storage processing for storing the chunks. If the chunk storage information does not exist in the first area, the controller stages the chunk storage information from the storage apparatus to the first area on condition that the first area has an unused ...

METHOD AND APPARATUS FOR CACHING DATA IN AN SOLID STATE DISK (SSD) OF A HYBRID DRIVE THAT INCLUDES THE SSD AND A HARD DISK DRIVE (HDD)

A system includes a read/write module and a caching module. The read/write module is configured to access a first portion of a recording surface of a rotating storage device. Data is stored on the first portion of the recording surface of the rotating storage device at a first density. The caching module is configured to cache data on a second portion of the recording surface of the rotating storage device at a second density. The second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device. The second density is less than the first density. 1. A hybrid drive comprising: a hard disk drive having a first data storage capacity, and', 'a solid state disk having a second data storage capacity, wherein the second data storage capacity of the solid state disk is lower than the first data storage capacity of the hard disk drive;, 'a storage system, wherein the storage system includes'}a host interface configured to be in communication with a host processor, the host processor including one or more levels of cache; anda disk controller coupled to the storage system, wherein the disk controller is configured to access the solid state disk as a final level of cache prior to the disk controller accessing the hard disk drive, (i) retrieve, in response to determining the data requested by the host processor is cached in the solid state disk, the data requested by the processor from the solid state disk, or', '(ii) retrieve, in response to determining the data requested by the host processor is not cached in the solid state disk, the data requested by the host processor from the hard disk drive., 'wherein in response to the host interface receiving a request for data that is not cached in the one or more levels of cache of the host processor, the disk controller is configured to determine first whether the data requested by the host processor is cached in the solid state disk ...

Demoting tracks from a first cache to a second cache by using an occupancy of valid tracks in strides in the second cache to consolidate strides in the second cache

Information is maintained on strides configured in a second cache and occupancy counts for the strides indicating an extent to which the strides are populated with valid tracks and invalid tracks. A determination is made of tracks to demote from a first cache. A first stride is formed including the determined tracks to demote. The tracks from the first stride are to a second stride in the second cache having an occupancy count indicating the stride is empty. A determination is made of a target stride in the second cache based on the occupancy counts of the strides in the second cache. A determination is made of at least two source strides in the second cache having valid tracks based on the occupancy counts of the strides in the second cache. The target stride is populated with the valid tracks from the source strides.

MANAGING READ REQUESTS FROM MULTIPLE REQUESTORS

Techniques are described herein for expanding the range of data targeted in I/O requests made by clients, so that the expanded range results in aligned I/O operations within the file system. Data that is included in the expanded range, but was not actually requested by the client, is trimmed off the data chunk returned by the file system, so that the client receives only the data required by the client. The blocks that contain the partially-read data are cached, so that they can be provided to the clients in response to subsequent I/O requests, without having to retrieve the blocks again from the file system. The I/O requests of multiple clients are handled by a read scheduler that uses a single global queue for all such requests. When appropriate, the read scheduler creates companionship relationships between the requests, and services the "companion" requests based on the data returned for the requests with which the companion requests are associated.

DETECTION AND PREVENTION OF DEADLOCK IN A STORAGE CONTROLLER FOR CACHE ACCESS VIA A PLURALITY OF DEMOTE MECHANISMS

A computational device determines whether one or more tasks are waiting for accessing a cache for more than a predetermined amount of time while least recently used (LRU) based replacement of tracks are being performed for the cache via demotion of tracks from a LRU list of tracks corresponding to the cache. In response to determining that one or more tasks are waiting for accessing the cache for more than the predetermined amount of time, in addition to continuing to demote tracks from the LRU list, a plurality of deadlock prevention demotion tasks demote tracks from the cache.

Media cache band cleaning

A data storage device includes a media cache and a main data store optimized for sequential reads and organized into bands. When the data storage device receives a read request from a host computing system, the requested data may be fragmented across the media cache and the main data store, causing constrained read throughput. Band rewrite operations to improve read throughput are selected based on a hit tracking list including a hit counter associated with each band on the main data store. The hit counter tracks the number of times a host computing system has requested data in logical block addresses corresponding to the various bands. The data storage device may select bands for band rewrite operations based on the number of hits in the associated hit tracking counters.

Considering a frequency of access to groups of tracks and density of the groups to select groups of tracks to destage

Provided are a computer program product, system, and method for considering a frequency of access to groups of tracks and density of the groups to select groups of tracks to destage. One of a plurality of densities for one of a plurality of groups of tracks is incremented in response to determining at least one of that the group is not ready to destage and that one of the tracks in the group in the cache transitions to being ready to destage. A determination is made of a group frequency indicating a frequency at which tracks in the group are modified. At least one of the density and the group frequency is used for each of the groups to determine whether to destage the group. The tracks in the group in the cache are destaged to the storage in response to determining to destage the group.

Managing read requests from multiple requestors

Techniques are disclosed for managing data requests from multiple requestors. According to one implementation, when a new data request is received, a determination is made as to whether a companion relationship should be established between the new data request and an existing data request. Such a companion relationship may be appropriate under certain conditions. If a companion relationship is established between the new data request and an existing data request, then when data is returned for one request, it is used to satisfy the other request as well. This helps to reduce the number of data accesses that need to be made to a data storage, which in turn enables system efficiency to be improved.

Populating a first stride of tracks from a first cache to write to a second stride in a second cache

Provided are a computer program product, system, and method for managing data in a cache system comprising a first cache, a second cache, and a storage system. A determination is made of tracks stored in the storage system to demote from the first cache. A first stride is formed including the determined tracks to demote. A determination is made of a second stride in the second cache in which to include the tracks in the first stride. The tracks from the first stride are added to the second stride in the second cache. A determination is made of tracks in strides in the second cache to demote from the second cache. The determined tracks to demote from the second cache are demoted.

Writing adjacent tracks to a stride, based on a comparison of a destaging of tracks to a defragmentation of the stride

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride.

Populating a second cache with tracks from a first cache when transferring management of the tracks from a first node to a second node

Provided are a computer program product, system, and method for populating a second cache with tracks from a first cache when transferring management of the tracks from a first node to a second node. Management of a first group of tracks in the storage managed by the first node is transferred to the second node managing access to a second group of tracks in the storage. After the transferring the management of the tracks, the second node manages access to the first and second groups of tracks and caches accessed tracks from the first and second groups in the second cache of the second node. The second cache of the second node is populated with the tracks in a first cache of the first node

Providing track access reasons for track accesses resulting in the release of prefetched cache resources for the track

Provided are a computer program product, system, and method for providing track access reasons for track accesses resulting in the release of prefetched cache resources for the track. A first request for a track is received from a process for which prefetched cache resources to a cache are held for a second request for the track that is expected. A track access reason is provided for the first request specifying a reason for the first request. The prefetched cache resources are released before the second request to the track is received. Indication is made in an unexpected released track list of the track and the track access reason for the first request.

Writing adjacent tracks to a stride, based on a comparison of a destaging of tracks to a defragmentation of the stride

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride.

Slice-Based Random Access Buffer for Data Interleaving

The disclosure is directed to a system and method for interleaving data utilizing a random access buffer that includes a plurality of independently accessible memory slots. The random access buffer is configured to store slices of incoming data sectors in free memory slots, where a free memory slot is identified by a status flag associated with a logical address of the free memory slot. Meanwhile, a label buffer is configured to store labels associated with the slices of the incoming data sectors in a sequence based upon an interleaving scheme. Media sectors including the interleaved data slices are read out from the memory slots of the random access buffer in order of the sequence of labels stored by the label buffer. As the media sectors are read out of the random access buffer, the corresponding memory slots are freed up for incoming slices of the next super-sector. 1. A system for interleaving data , comprising:a slice divider configured to receive incoming data sectors of a super-sector, the slice divider being further configured to divide the incoming data sectors into slices;a random access buffer including memory slots for storing data sector slices, the random access buffer being configured to store the slices of the incoming data sectors in free memory slots, wherein a free memory slot is identified by a status flag associated with a logical address of the free memory slot;a label buffer configured to store labels associated with the slices of the incoming data sectors in a sequence based upon an interleaving scheme; anda processor in communication with the random access buffer and the label buffer, the processor being configured to read out media sectors corresponding to the super-sector, wherein a media sector includes interleaved data slices read out from the memory slots of the random access buffer in order of the sequence of labels stored by the label buffer.2. The system of claim 1 , wherein the processor is configured to read out the media sectors ...

Transfer track format information for tracks in cache at a primary storage system to a secondary storage system to which tracks are mirrored to use after a failover or failback

Provided are a computer program product, system, and method to transfer track format information for tracks in cache at a primary storage system to a secondary storage system to which tracks are mirrored to use after a failover or failback. In response to a failover from the primary storage system to the secondary storage system, the primary storage system adds a track identifier of the track and track format information indicating a layout of data in the track, indicated in track metadata for the track in the primary storage, to a cache transfer list. The primary storage system transfers the cache transfer list to the secondary storage system to use the track format information in the cache transfer list for a track staged into the secondary cache having a track identifier in the cache transfer list.

Invalidating track format information for tracks demoted from cache

Provided are a computer program product, system, and method for invalidating track format information for tracks demoted from cache. Demoted tracks demoted from the cache are indicated in a demoted track list. Track format information is saved for the demoted tracks. The track format information indicates a layout of data in the demoted tracks, wherein the track format information for the demoted tracks is used when the demoted tracks are staged back into the cache. An operation is initiated to invalidate a metadata track of the metadata tracks in the storage. Demoted tracks indicated in the demoted track list having metadata in the metadata track to invalidate are removed. The track format information for the demoted tracks having metadata in the metadata track to invalidate is removed.

Writing adjacent tracks to a stride, based on a comparison of a destaging of tracks to a defragmentation of the stride

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride.

Restriction of validation to active tracks in non-volatile storage during a warmstart recovery

A storage system, maintains a cache and a non-volatile storage. Active tracks in the non-volatile storage are determined. The determined active tracks in the non-volatile storage are validated between the cache and the non-volatile storage during a warmstart recovery.

USING MIRROR INDICATORS TO INDICATE WHETHER TO MIRROR TRACKS IN A DATA SET IN A PRIMARY VOLUME MIRRORED TO A SECONDARY VOLUME

Provided are a computer program product, system, and method for using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume. A table includes a mirror indicator for each of a plurality of tracks in at least one data set in the primary volume indicating whether a track is to be mirrored to the secondary volume. In response to a write command of write data for one of the tracks in the primary volume, creating a record set in a cache for the primary volume including write data for the track to transfer to the secondary volume in response to the mirror indicator for the track indicating that the track is to be mirrored. The write data in the record set is transferred from the cache to the secondary volume. 1. A computer program product for mirroring data between a primary volume and a secondary volume , wherein the computer program product comprises a computer readable storage medium having program instructions embodied therewith , the program instructions executable by a processor to cause operations , the operations comprising:maintaining a table including a mirror indicator for each of a plurality of tracks in at least one data set in the primary volume indicating whether a track is to be mirrored to the secondary volume; andin response to a write command of write data for one of the tracks in the primary volume, creating a record set in a cache for the primary volume including write data for the track to transfer to the secondary volume in response to the mirror indicator for the track indicating that the track is to be mirrored, wherein the write data in the record set is transferred from the cache to the secondary volume.2. The computer program product of claim 1 , wherein a record set is not created in the cache for the write data if the mirror indicator indicates that the track is not to be mirrored.35-. (canceled)6. The computer program product of claim 1 , wherein the operations further comprise ...

HANDLING CACHE AND NON-VOLATILE STORAGE (NVS) OUT OF SYNC WRITES

Provided are techniques for handling cache and Non-Volatile Storage (NVS) out of sync writes. At an end of a write for a cache track of a cache node, a cache node uses cache write statistics for the cache track of the cache node and Non-Volatile Storage (NVS) write statistics for a corresponding NVS track of an NVS node to determine that writes to the cache track and to the corresponding NVS track are out of sync. The cache node sets an out of sync indicator in a cache data control block for the cache track. The cache node sends a message to the NVS node to set an out of sync indicator in an NVS data control block for the corresponding NVS track. The cache node sets the cache track as pinned non-retryable due to the write being out of sync and reports possible data loss to error logs. 118-. (canceled)19. A computer program product , the computer program product comprising a computer readable storage medium having program code embodied therewith , the program code executable by at least one processor to perform:at an end of a write for an Non-Volatile Storage (NVS) track of the NVS node, sending, with the NVS node, the NVS write statistics to a cache node, wherein, at an end of a write for a corresponding cache track of the cache node, the cache node determines that writes to the corresponding cache track and to the NVS track are out of sync based on identifying a different number of the writes to the NVS track than to the corresponding cache track using the NVS write statistics and cache write statistics;receiving, with the NVS node, a message from the cache node to set an NVS out of sync indicator in an NVS data control block for the NVS track to indicate that the writes to the NVS track and the corresponding cache track are out of sync;setting, with the NVS node, the NVS out of sync indicator in the NVS data control block for the NVS track, wherein the cache node, sets a cache out of sync indicator in a cache data control block for the corresponding cache track to ...

METHOD AND SYSTEM FOR PRESERVING DATA OF A STORAGE DEVICE

Various embodiments of a method and system for preserving data of a data storage device are disclosed. The method can include determining a number of times data is written to a target track of a storage medium; rewriting data from a track adjacent the target track if the number of times data is written to the target track exceeds a first predetermined threshold; determining a number of times data is rewritten to the adjacent track; copying data from the target track to a first storage location of a media cache if the number of times data is rewritten to the adjacent track exceeds a second predetermined threshold; writing subsequent data designated for the target track to the first storage location of the media cache; and relocating data from the first storage location of the media cache to the target track. 21. The method of claim , wherein the first predetermined threshold is at least 100 times.31. The method of claim , wherein the second predetermined threshold is at least 100 times.41. The method of claim , further comprising reassigning an address of the data that is copied from the target track to the first storage location of the media cache before writing subsequent data designated for the target track to the first storage location of the media cache.51. The method of claim , wherein the time threshold equals 24 hours.61. The method of claim , further comprising erasing the first storage location of the media cache after data from the first storage location of the media cache is relocated to the target track.71. The method of claim , wherein the media cache is located on the storage medium.81. The method of claim , wherein the media cache is located on non-volatile memory.91. The method of claim , further comprising rewriting data from a second track adjacent the target track if the number of times data is written to the target track exceeds a third predetermined threshold , wherein the target track is positioned between the adjacent track and the second ...

INTEGRATION OF APPLICATION INDICATED MINIMUM TIME TO CACHE AND MAXIMUM TIME TO CACHE TO LEAST RECENTLY USED TRACK DEMOTING SCHEMES IN A CACHE MANAGEMENT SYSTEM OF A STORAGE CONTROLLER

A computational device receives indications of a minimum retention time and a maximum retention time in cache for a first plurality of tracks, wherein no indications of a minimum retention time or a maximum retention time in the cache are received for a second plurality of tracks. A cache management application demotes a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time. The cache management application demotes the track of the first plurality of tracks, in response to determining that the track has been in the cache for a time that exceeds the maximum retention time. 124-. (canceled)25. A method , comprising:receiving indications of a minimum retention time and a maximum retention time in a cache for a first plurality of tracks, wherein no indications of the minimum retention time or the maximum retention time in the cache are received for a second plurality of tracks; anddemoting, by a cache management application, a track of the first plurality of tracks from the cache even if the track has not been in the cache for a time that exceeds the minimum retention time, in response to predetermined conditions being satisfied.26. The method of claim 25 , the method further comprising:demoting a track of the second plurality of tracks from the cache, in response to determining that the track of the second plurality of tracks is a least recently used (LRU) track in a LRU list.27. The method of claim 25 , wherein the minimum retention time is indicative of a preference of a host application to maintain the first plurality of tracks in the cache for at least the minimum retention time claim 25 , and wherein the maximum retention time is indicative of a preference of the host application to maintain the first plurality of tracks in the cache for no more than the maximum ...

Wait classified cache writes in a data storage system

In one embodiment, a task control block (TCB) for allocating cache storage such as cache segments in a multi-track cache write operation may be enqueued in a wait queue for a relatively long wait period, the first time the task control block is used, and may be re-enqueued on the wait queue for a relatively short wait period, each time the task control block is used for allocating cache segments for subsequent cache writes of the remaining tracks of the multi-track cache write operation. As a result, time-out suspensions caused by throttling of host input-output operations to facilitate cache draining, may be reduced or eliminated. It is appreciated that wait classification of task control blocks in accordance with the present description may be applied to applications other than draining a cache. Other features and aspects may be realized, depending upon the particular application.

INVALIDATING TRACK FORMAT INFORMATION FOR TRACKS IN CACHE

Provided are a computer program product, system, and method for invalidating track format information for tracks in cache. Demoted tracks demoted from the cache are indicated in a demoted track list. Track format information is saved for the demoted tracks. The track format information indicates a layout of data in the demoted tracks, wherein the track format information for the demoted tracks is used when the demoted tracks are staged back into the cache. An operation is initiated to invalidate a metadata track of the metadata tracks in the storage. Demoted tracks indicated in the demoted track list having metadata in the metadata track to invalidate are removed. The track format information for the demoted tracks having metadata in the metadata track to invalidate is removed. 122-. (canceled)23. A computer program product for managing metadata on tracks in a storage cached in a cache in a portion of a memory , the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that is executable to perform operations , the operations comprising:determining tracks having metadata in a metadata track to invalidate; andindicating track format codes, in cache control blocks for tracks whose metadata is in the metadata track to invalidate, as invalid, wherein valid track format codes are used to determine corresponding track format metadata having track format layout information used to access tracks.24. The computer program product of claim 23 , wherein the operations further comprise:receiving a read/write request to a target track on a first channel;failing the read/write request on the first channel in response to a track format code, in a cache control block for the target track, indicated as invalid; andprocessing the read/write request on the first channel using track format layout information in track format metadata corresponding to the track format code, in the cache control block for the target ...

ALLOCATING CACHE MEMORY ON A PER DATA OBJECT BASIS

Systems, methods, and software described herein allocate cache memory to job processes executing on a processing node. In one example, a method of allocating cache memory to a plurality of job process includes identifying the plurality of job processes executing on a processing node, and identifying a data object to be accessed by the plurality of job processes. The method further provides allocating a portion of the cache memory to each job process in the plurality of job processes and, for each job process in the plurality of job processes, identifying a segment of data from the data object, wherein the segment of data comprises a requested portion of data and a predicted portion of data. The method also includes providing the segments of data to the allocated portions of the cache memory. 1. A method of allocating cache memory to a plurality of job processes , the method comprising:in a processing system, identifying the plurality of job processes executing on a processing node;identifying a data object to be accessed by the plurality of job processes;in response to identifying the data object, allocating a portion of the cache memory to each job process in the plurality of job processes;for each job process in the plurality of job processes, identifying a segment of data from the data object, wherein the segment of data comprises a requested portion of data and a predicted portion of data; andproviding the segments of data to the allocated portions of the cache memory.2. The method of wherein the processing node comprises a real computing system.3. The method of wherein the processing node comprises a virtual element executing on a host computing system.4. The method of wherein the cache memory comprises shared memory accessible by processes on the host computing system and the plurality of job processes executing on the virtual element.5. The method of wherein the plurality of job processes comprises a plurality of java virtual machines.6. The method of wherein ...

INVOKING DEMOTE THREADS ON PROCESSORS TO DEMOTE TRACKS FROM A CACHE

Provided are a computer program product, system, and method for invoking demote threads on processors to demote tracks from a cache. A plurality of demote ready lists indicate tracks eligible to demote from the cache. In response to determining that a number of free cache segments in the cache is below a free cache segment threshold, a determination is made of a number of demote threads to invoke on processors based on the number of free cache segments and the free cache segment threshold. The determined number of demote threads are invoked to demote tracks in the cache indicated in the demote ready lists, wherein each invoked demote thread processes one of the demote ready lists to select tracks to demote from the cache to free cache segments in the cache. 123-. (canceled)24. A computer program product for managing tracks in a storage in a cache , the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that when executed performs operations , the operations comprising:determining a number of demote threads to invoke on processors based on a number of free cache segments; andinvoking the number of demote threads to demote tracks in the cache, wherein each invoked demote thread demotes tracks from the cache to free cache segments in the cache.25. The computer program product of claim 24 , wherein the determining the number of demote threads to invoke comprises:determining to invoke one demote thread on each of the processors in response to the number of free cache segments in the cache being below a free cache segment threshold; anddetermining to invoke one demote thread on less than all of the processors in response to the number of free cache segments being greater than the free cache segment threshold.26. The computer program product of claim 25 , wherein the free cache segment threshold comprises a first free cache segment threshold claim 25 , and wherein determining the number of demote ...

INTEGRATION OF APPLICATION INDICATED MINIMUM TIME TO CACHE FOR A TWO-TIERED CACHE MANAGEMENT MECHANISM

An indication is received from a host application of a first minimum retention time in a cache comprising a first type of memory and a second type of memory for a first plurality of tracks, wherein the first minimum retention time is not indicated for a second plurality of tracks. Based on the first minimum retention time, a second minimum retention time is set for the first plurality of tracks for the first type of memory and a third minimum retention time is set for the first plurality of tracks for the second type of memory. A track of the first plurality of tracks is demoted from the first type of memory, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the first type of memory and the track has been in the first type of memory for a time that exceeds the second minimum retention time. 1. A method , comprising:receiving from a host application, an indication of a first minimum retention time in a cache comprising a first type of memory and a second type of memory for a first plurality of tracks, wherein the first minimum retention time is not indicated for a second plurality of tracks;based on the first minimum retention time, setting a second minimum retention time for the first plurality of tracks for the first type of memory and a third minimum retention time for the first plurality of tracks for the second type of memory; anddemoting a track of the first plurality of tracks from the first type of memory, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the first type of memory and the track has been in the first type of memory for a time that exceeds the second minimum retention time.2. The method of claim 1 , wherein the first type of memory is a dynamic random access memory (DRAM) cache and the second type of memory is a storage class memory (SCM) cache claim 1 , and wherein the second minimum retention time is a DRAM cache minimum retention ...

WRITING ADJACENT TRACKS TO A STRIDE, BASED ON A COMPARISON OF A DESTAGING OF TRACKS TO A DEFRAGMENTATION OF THE STRIDE

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride. 1. A method , comprising:receiving a request to write one or more tracks; andwriting the one or more tracks to a stride by creating contiguous free space on the stride either via destaging of selected tracks or via defragmentation of the stride, in response to determining whether the destaging or the defragmentation is faster.2. The method of claim 1 , wherein tracks that are numbered consecutively are placed adjacent to each other in the contiguous free space.3. The method of claim 1 , wherein the stride is represented in a cache claim 1 , the method further comprising:determining, by a management application executing in a controller coupled to a redundant array of independent disks and the cache, whether a first estimated duration of time to perform a number of operations required to destage the selected tracks from the stride represented in the cache is a smaller amount of time in comparison to a second estimated duration of time required to defragment compressed data in the stride represented in the cache; anddestaging the selected tracks from the cache, by a destaging application executing in the controller, in response to determining that the first estimated duration of time is a smaller amount of time in comparison to the second estimated duration of time.4. The method of claim 3 , the method further comprising:defragmenting, by a defragmentation application executing in the controller, the stride, in response to determining that the first estimated duration of time ...

Method and Apparatus for Cache Slot Allocation Based on Data Origination Location or Final Data Destination Location

Operational information in a storage system is collected regarding storage media storage tiers, devices, drives, tracks on drives, and logical storage layers, to determine an estimated amount of time it will take to write data from cache to the intended drive when a new write operation arrives at the storage system. This information is then used to decide which type of cache is most optimal to store the data for the write operation, based on the estimated amount of time it will take to write data out from the cache. By allocating cache slots from a faster cache to write operations that are expected to quickly be written out to memory, and allocating cache slots from the slower cache to write operations that are expected to take more time to be written out to memory, it is possible to increase the availability of the cache slots in the faster cache.

USING MIRROR INDICATORS TO INDICATE WHETHER TO MIRROR TRACKS IN A DATA SET IN A PRIMARY VOLUME MIRRORED TO A SECONDARY VOLUME

Provided are a computer program product, system, and method for using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume. A table includes a mirror indicator for each of a plurality of tracks in at least one data set in the primary volume indicating whether a track is to be mirrored to the secondary volume. In response to a write command of write data for one of the tracks in the primary volume, creating a record set in a cache for the primary volume including write data for the track to transfer to the secondary volume in response to the mirror indicator for the track indicating that the track is to be mirrored. The write data in the record set is transferred from the cache to the secondary volume. 122-. (canceled)23. A computer program product for mirroring data between a primary volume and a secondary volume , wherein the computer program product comprises a computer readable storage medium having program instructions embodied therewith , the program instructions executable by a processor to cause operations , the operations comprising:in response to an operation to allocate tracks in a da set to the primary volume, set a mirror indicator, for each track in the data set to allocate that is indicated in a data set mirror list to mirror, that the track is to be mirrored to the secondary volume; andtransferring write data for a track in the primary volume to the secondary volume in response to a mirror indicator for the track to write indicating that the track is to be mirrored.24. The computer program product of claim 23 , wherein the mirror indicator indicates no mirroring for tracks in the data set being allocated not specified in the data set mirror list to mirror.25. The computer program product of claim 23 , wherein the operations further comprise:receiving from a user the data set mirror list for the tracks of the data set to allocate to the primary volume.26. The computer program product of ...

USING AN ACCESS INCREMENT NUMBER TO CONTROL A DURATION DURING WHICH TRACKS REMAIN IN CACHE

Provided are a computer program product, system, and method for using an access increment number to control a duration during which tracks remain in cache. Tracks in a storage in the cache are indicated in a cache list. For each of the tracks indicated in the cache list, an access value is updated when one of the tracks is accessed in the cache. An access to a track in the cache indicated in the cache list is received. A determination is made as to whether an access increment number for the accessed track, wherein the access increment number is greater than one. The access value for the accessed track is incremented by the determined access increment number in response to the track being accessed in the cache. The access value for one of the tracks is used to determine whether to initiate to demote the track from the cache. 123-. (canceled)24. A computer program product for managing tracks in a storage in a cache , the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that when executed performs operations , the operations comprising:indicating tracks in the storage stored in the cache in a cache list;indicating for each of the tracks indicated in the cache list an access increment number;receiving an application access increment number provided by an application for a track comprising one of a plurality of values used to control a duration during which the track is maintained in the cache;setting the access increment number indicated for the track to the application access increment number;in response to a request for a requested track in the cache, incrementing an access value for the requested track by the access increment number indicated for the track; andusing an access value for a track in the cache to determine whether to demote the track from the cache.25. The computer program product of claim 24 , wherein the operations further comprise:receiving a request for a track from an ...

SHINGLED MAGNETIC RECORDING STORAGE SYSTEM

The disclosed technology provides a method that reduces time to recover in storage systems. In one implementation, the method comprises entering an idle status, determining if there is an incomplete band update operation, invalidating a media scratch pad (MSP) by clearing headers responsive to determining there is no incomplete band update operation, performing a power cycle, reading an MSP header, and determining if an MSP header is valid. If a rude power cycle occurs and the MSP header is determined to be valid, an MSP is examined, and restored if required. If a safe power cycle occurs, an MSP restore operation is not required, reducing time to recover. 1. A method comprising:determining if there is an incomplete band update operation; andclearing media scratch pad (MSP) headers responsive to determining there is no incomplete band update operation.2. The method of claim 1 , wherein the determining if there is an incomplete band update operation is performed when a drive to entering an idle state.3. The method of claim 1 , wherein the determining if there is an incomplete band update operation is performed upon receiving at least one of a standby command and sleep command.4. The method of claim 1 , further comprising:performing a power cycle; andreading an MSP header.5. The method of claim 4 , further comprising:determining if the MSP header is valid.6. The method of claim 5 , further comprising:performing the recovery process responsive to determining the MSP header is invalid.7. The method of claim 6 , further comprising:performing a ready to host operation.8. The method of claim 5 , further comprising:examining an MSP responsive to determining the MSP header is valid.9. The method of claim 8 , further comprising:performing an MSP restore operation if required.10. The method of claim 9 , further comprising:performing a ready to host operation.11. A storage device system claim 9 , comprising: determine if there is an incomplete band update operation in a storage ...

PERMUTATION APPARATUS, PERMUTATION METHOD, AND PROGRAM

To perform permutation processing at high speed. A number-of-elements determination unit () calculates the number of elements to be contained in each allocation destination. A start position determination unit () calculates a start position corresponding to each allocation destination. An allocation destination determination unit () calculates a sequence of values representing allocation destinations in a buffer. A permutation generating unit () calculates a sequence of values representing permutation destinations within the respective allocation to destination. An initial position setting unit () sets the start position into a value indicating a position within processing corresponding to each allocation destination. A rearrangement unit () sets the elements of a vector into the respective allocation destinations in the buffer. A permutation execution unit () generates an output vector by executing an arbitrary inverse permutation algorithm on the respective allocation destinations. 1. A permutation apparatus ,{'sup': →', '→', '→', '→, 'sub': i', 'i, 'where D is a predetermined number of segmentations, a is a vector of length m, b is a sequence of values less than D representing allocation destinations in a buffer, x is a sequence of values representing permutation destinations within the respective allocation destinations, d is a vector representing a buffer of length m, i is each integer equal to or greater than 0 and less than D, j is each integer equal to or greater than 0 and less than m, Sis a start position corresponding to an i-th allocation destination, and Nis the number of elements to be contained in the i-th allocation destination,'}the permutation apparatus comprising processing circuitry configured to:{'sub': i', 'i, 'set, for each integer i, the start position Sinto a value Pindicating a position within processing corresponding to the i-th allocation destination;'}{'sub': j', 'b_j', 'P_b_j, 'sup': →', '→, 'set, for each integer j, a j-th element aof ...

CACHING SYSTEMS AND METHODS FOR HARD DISK DRIVES AND HYBRID DRIVES

A system includes a read/write module and a caching module. The read/write module is configured to access a first portion of a recording surface of a rotating storage device. Data is stored on the first portion of the recording surface of the rotating storage device at a first density. The caching module is configured to cache data on a second portion of the recording surface of the rotating storage device at a second density. The second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device. The second density is less than the first density. 1a read/write module configured to access a first portion of a recording surface of a rotating storage device, wherein data is stored on the first portion of the recording surface of the rotating storage device at a first density; anda caching module configured to cache data on a second portion of the recording surface of the rotating storage device at a second density,wherein the second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device, andwherein the second density is less than the first density.. A system comprising: This application is a continuation of U.S. application Ser. No. 15/204,368, filed on Jul. 7, 2016, which is a continuation of U.S. application Ser. No. 14/702,078 (now U.S. Pat. No. 9,454,991), filed May 1, 2015, which claims the benefit of U.S. Provisional Application No. 61/987,947, filed on May 2, 2014. This application is related to U.S. patent application Ser. No. 14/519,826, filed on Oct. 21, 2014, which claims the benefit of U.S. Provisional Application No. 61/893,662, filed on Oct. 21, 2013, U.S. Provisional Application No. 61/893,675, filed on Oct. 21, 2013, and U.S. Provisional Application No. 61/893,683, filed on Oct. 21, 2013, and U.S. Provisional Application No. 61/895,049, filed Oct. 24, 2013. The ...

Storage drive dependent track removal in a cache for storage

In one embodiment, storage drive dependent track removal processing logic performs destage tasks for tracks cached in a cache as a function of whether the storage drive is classified as a fast class or as slow class of storage drives, for example. In one embodiment, a destage task configured for a slow class storage drive, transfers an entry for a track selected for destaging from a main cache list to a wait cache list to await destaging to the slow class drive. A destage task configured for a fast class storage drive allows the cache list entry for the selected track to remain on the main cache list while the selected track is being destaged to the fast class storage drive, thereby bypassing the transfer of the entry to a wait cache list. Other features and aspects may be realized, depending upon the particular application.

POPULATING A SECOND CACHE WITH TRACKS FROM A FIRST CACHE WHEN TRANSFERRING MANAGEMENT OF THE TRACKS FROM A FIRST NODE TO A SECOND NODE

Provided are a computer program product, system, and method for populating a second cache with tracks from a first cache when transferring management of the tracks from a first node to a second node. Management of a first group of tracks in the storage managed by the first node is transferred to the second node managing access to a second group of tracks in the storage. After the transferring the management of the tracks, the second node manages access to the first and second groups of tracks and caches accessed tracks from the first and second groups in the second cache of the second node. The second cache of the second node is populated with the tracks in a first cache of the first node 122-. (canceled)23. A computer program product for transferring management of tracks in a storage , the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that is executable to perform operations , the operations comprising:transfer management of tracks from a first node to a second node that are stored in a first cache of the first node; andin response to transferring management of the tracks from the first node to the second node comprises, transferring a tracks maintained in the first cache from the first cache to a second cache.24. The computer program product of claim 23 , wherein the transferring the tracks from the first cache to the second cache comprises a first number of tracks claim 23 , wherein the operations further comprise:transferring a second number of tracks maintained in the first cache and stored in a storage from the storage to the second cache.25. The computer program product of claim 24 , wherein the operations further comprise:sending a cache transfer list indicating the first number and the second number of tracks to the second node to cause the second node to access the tracks from the first cache and the storage to transfer to the second cache.26. The computer program product of ...

CONSIDERING A FREQUENCY OF ACCESS TO GROUPS OF TRACKS AND DENSITY OF THE GROUPS TO SELECT GROUPS OF TRACKS TO DESTAGE

Provided are a computer program product, system, and method for considering a frequency of access to groups of tracks and density of the groups to select groups of tracks to destage. One of a plurality of densities for one of a plurality of groups of tracks is incremented in response to determining at least one of that the group is not ready to destage and that one of the tracks in the group in the cache transitions to being ready to destage. A determination is made of a group frequency indicating a frequency at which tracks in the group are modified. At least one of the density and the group frequency is used for each of the groups to determine whether to destage the group. The tracks in the group in the cache are destaged to the storage in response to determining to destage the group. 122-. (canceled)23. A computer program product for selecting tracks to destage from a cache to a storage , the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that when executed by a processor performs operations , the operations comprising:determining a number of tracks in a group of tracks, of a plurality of groups of tracks, that are ready to destage;determining, for each of the groups of tracks, a group frequency indicating a frequency at which tracks in the group are modified;determining a group to destage based on at least one of the group frequency and the number of tracks in the group that are ready to destage; anddestaging the tracks in the determined group in the cache to the storage in response to determining to determining the group to destage.24. The computer program product of claim 23 , wherein the number of tracks in a group of tracks that are ready to destage is incremented in response to determining at least one of that all tracks in the groups are not ready to destage and that one of the tracks in the group in the cache transitions to being ready to destage.25. The computer program ...

Invalidating ckd data tracks prior to unpinning

A method for invalidating a track of data on a storage drive in preparation to unpin the track is disclosed. In one embodiment, such a method includes invalidating certain metadata associated with a track of data residing on a storage drive of a storage system. The method further creates, in cache of the storage system, an invalid track image associated with the track. The method destages, from the cache, the invalid track image to the storage drive. Once the invalid track image is destaged, the method may unpin the track in cache, thereby enabling destages of the track from the cache to the storage drive going forward. A corresponding system and computer program product are also disclosed.

INTEGRATION OF APPLICATION INDICATED MAXIMUM TIME TO CACHE TO LEAST RECENTLY USED TRACK DEMOTING SCHEMES IN A CACHE MANAGEMENT SYSTEM OF A STORAGE CONTROLLER

A computational device receives an indication that specifies a maximum retention time in cache for a first plurality of tracks, wherein no maximum retention time is specified for a second plurality of tracks. A plurality of insertions points are generated in a least recently used (LRU) list, wherein different insertion points in the LRU list correspond to different amounts of time that a track of the first plurality of tracks is expected to be retained in the cache, wherein the LRU list is configured to demote both tracks of the first plurality of tracks and the second plurality of tracks from the cache. 1. A method , comprising:receiving, by a computational device, an indication that specifies a maximum retention time in cache for a first plurality of tracks, wherein no maximum retention time is specified for a second plurality of tracks; andgenerating a plurality of insertions points in a least recently used (LRU) list, wherein different insertion points in the LRU list correspond to different amounts of time that a track of the first plurality of tracks is expected to be retained in the cache, wherein the LRU list is configured to demote both tracks of the first plurality of tracks and the second plurality of tracks from the cache.2. The method of claim 1 , the method further comprising:in response to determining that a track is of the first plurality of tracks, determining an insertion point whose corresponding amount of time is closest to a maximum retention time for the track of the first plurality of tracks; andadding the determined track to the determined insertion point.3. The method of claim 2 , the method further comprising:in response to adding the determined track to the determined insertion point, moving insertion points by one track to accommodate the adding of the determined track.4. The method of claim 3 , in response to the moving of the insertion points claim 3 , adding a new insertion point to a most recently used (MRU) end of the LRU list if a ...

INTEGRATION OF APPLICATION INDICATED MINIMUM TIME TO CACHE TO LEAST RECENTLY USED TRACK DEMOTING SCHEMES IN A CACHE MANAGEMENT SYSTEM OF A STORAGE CONTROLLER

A minimum retention time in cache is indicated for a first plurality of tracks, where no minimum retention time is indicated for a second plurality of tracks. A cache management application demotes a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time. 1. A method , comprising:indicating a minimum retention time in cache for a first plurality of tracks, wherein no minimum retention time is indicated for a second plurality of tracks; anddemoting, by a cache management application, a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time.2. The method of claim 1 , the method further comprising:demoting the track of the first plurality of tracks from the cache, in response to determining that the first plurality of tracks exceeds a predetermined percentage of tracks in the cache.3. The method of claim 1 , the method further comprising:demoting the track of the first plurality of tracks from the cache, in response to determining that a predetermined percentage of tracks towards a least recently used (LRU) end of a LRU list are not eligible for demotion, wherein tracks in the predetermined percentage are included in the first plurality of tracks and are not eligible for demotion because the tracks have not been in the cache for a time that exceeds the minimum retention time.4. The method of claim 1 , the method further comprising:demoting a track of the second plurality of tracks from the cache, in response to determining that the track of the second plurality of tracks is a least recently used (LRU) track in the LRU list.5. The method of claim 1 , wherein the track of ...

INTEGRATION OF APPLICATION INDICATED MINIMUM TIME TO CACHE AND MAXIMUM TIME TO CACHE TO LEAST RECENTLY USED TRACK DEMOTING SCHEMES IN A CACHE MANAGEMENT SYSTEM OF A STORAGE CONTROLLER

A computational device receives indications of a minimum retention time and a maximum retention time in cache for a first plurality of tracks, wherein no indications of a minimum retention time or a maximum retention time in the cache are received for a second plurality of tracks. A cache management application demotes a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time. The cache management application demotes the track of the first plurality of tracks, in response to determining that the track has been in the cache for a time that exceeds the maximum retention time. 1. A method , comprising:receiving indications of a minimum retention time and a maximum retention time in cache for a first plurality of tracks, wherein no indications of a minimum retention time or a maximum retention time in the cache are received for a second plurality of tracks;demoting, by a cache management application, a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time; anddemoting, by the cache management application, the track of the first plurality of tracks, in response to determining that the track has been in the cache for a time that exceeds the maximum retention time.2. The method of claim 1 , the method further comprising:demoting a track of the second plurality of tracks from the cache, in response to determining that the track of the second plurality of tracks is a least recently used (LRU) track in the LRU list.3. The method of claim 1 , wherein the minimum retention time is indicative of a preference of a host application to maintain the first plurality of tracks in the ...

Sidefiles for management of data written via a bus interface to a storage controller during consistent copying of data

Remote copy operations are performed to copy data from a primary storage controller to a secondary storage controller, wherein input/output (I/O) requests are received at the primary storage controller from a host both via a bus interface and a network interface while the remote copy operations are in progress, and wherein consistency groups are formed during the remote copy operations to copy the data consistently. A relocation is performed of data written via the bus interface for a current consistency group from a cache to a sidefile, and subsequently data written via the bus interface for a next consistency group is stored in the cache.

Cache management method and cache device using sector set

Data storage and caching architecture

An extent record for an extent based data buffer that includes a host pointer that links the extent record to a next host extent record of a host extent record set, and a storage device pointer that links the extent record to a next storage device extent record of a storage device extent record set. Also, a system for transferring data between a host and a storage device that includes a data buffer coupled to the host and the storage device, where memory in the data buffer is divided into one or more extents, an extent table associated with the data buffer, where the extent table includes at least one extent record, an LBA chain table coupled to the host and the extent table, and a track section table coupled to the storage device and the extent table.

Data storage and caching architecture

An extent record for an extent based data buffer that includes a host pointer that links the extent record to a next host extent record of a host extent record set, and a storage device pointer that links the extent record to a next storage device extent record of a storage device extent record set. Also, a system for transferring data between a host and a storage device that includes a data buffer coupled to the host and the storage device, where memory in the data buffer is divided into one or more extents, an extent table associated with the data buffer, where the extent table includes at least one extent record, an LBA chain table coupled to the host and the extent table, and a track section table coupled to the storage device and the extent table.

Magnetic disk apparatus and control method thereof

实施方式涉及磁盘装置及其控制方法。根据实施方式，磁盘装置具备磁盘、第1磁头、第2磁头、第1致动器、第2致动器、缓冲存储器以及控制电路。第1致动器使第1磁头移动。第2致动器使第2磁头移动。磁盘具有多个第1存储区域。控制电路使用第1磁头以及第1致动器将多个第1存储区域中的第2存储区域所保存的第1数据向缓冲存储器读出。控制电路执行如下控制：与第1数据的读出并行地，使用第2磁头以及第2致动器向多个第1存储区域中的与第2存储区域不同的第3存储区域写入缓冲存储器所保存的第1数据所对应的第2数据。

Integration of application indicated maximum time to cache to least recently used track demoting schemes in a cache management system of a storage controller

A computational device receives an indication that specifies a maximum retention time in cache for a first plurality of tracks, wherein no maximum retention time is specified for a second plurality of tracks. A plurality of insertions points are generated in a least recently used (LRU) list, wherein different insertion points in the LRU list correspond to different amounts of time that a track of the first plurality of tracks is expected to be retained in the cache, wherein the LRU list is configured to demote both tracks of the first plurality of tracks and the second plurality of tracks from the cache.

Storage system

The storage system includes a disk controller for receiving write commands from a computer, and a plurality of disk devices in which data is written in accordance with the control of the disk controller. The size of the first block which constitutes the data unit handled in the execution of the input/output processing of the data in accordance with the write command by the disk controller is different from the size of the second block which constitutes the data unit handled in the execution of the input/output processing of data by the plurality of disk devices. The disk controller issues an instruction for the writing of data to the disk devices using a third block unit of a size corresponding to a common multiple of the size of the first block and the size of the second block.

Shingled magnetic recording storage system

The disclosed technology includes methods and systems that reduce off-track write retry operations in shingled magnetic recording systems. In one implementation, the method includes writing data to an initial track, determining which side of the initial track is a shingled side, calculating a percentage of position error signal (PES) at a shingled side end of the initial track (PES 1 ) when an off-track write operation occurs, determining whether the PES 1 meets a first pre-determined threshold, continue writing data to a second track responsive to determining the PES 1 is below a first pre-determined threshold, calculating a percentage of PES at a shingled side end of the second track (PES 2 ), determining whether a combined value of PES 1 and PES 2 is above a second predetermined threshold to determine a probability value of the initial track being erased, and continue writing to a third track if the combined value is below the second predetermined threshold.

Media based cache for data storage device

Write commands are received for a Data Storage Device (DSD) to store write data in a plurality of corresponding write locations on at least one disk of the DSD. At least a portion of the write data is cached in at least one Media Based Cache (MBC) region of the at least one disk based on a write cache policy for determining which write data is eligible for caching in the at least one MBC region. The at least one MBC region is used to cache data to be stored in other locations on the at least one disk. During an active time period when host commands are performed on the at least one disk, a portion of an I/O bandwidth for performing commands is used to copy the at least a portion of the write data to corresponding write locations of the plurality of corresponding write locations.

Using a machine learning module to perform destages of tracks with holes in a storage system

In response to an end of track access for a track in a cache, a determination is made as to whether the track has modified data and whether the track has one or more holes. In response to determining that the track has modified data and the track has one or more holes, an input on a plurality of attributes of a computing environment in which the track is processed is provided to a machine learning module to produce an output value. A determination is made as to whether the output value indicates whether one or more holes are to be filled in the track. In response to determining that the output value indicates that one or more holes are to be filled in the track, the track is staged to the cache from a storage drive.

Storage system

在存储系统的控制部处理的数据单位和记录媒体处理的数据单位不同时，探求用于使其控制部也能进行向记录媒体的数据输入输出处理的技术。存储系统，具有从计算机接收写命令的磁盘控制器和根据磁盘控制器的控制写入数据的多个磁盘装置。在磁盘控制器根据写命令实行数据的输入输出处理时作为处理数据单位的第一块的尺寸、和在多个磁盘装置的各个实行数据输入输出处理时作为处理数据单位的第二块的尺寸不同。而且，磁盘控制器用具有第一块的尺寸和第二块的尺寸的公倍数的尺寸的第三块单位，对磁盘装置指示数据的写入。

Data storage hierarchy and its use for data storage space management

In a data storage hierarchy a data-storage buffer (15) transfers data signals with other units (10, 14) in relatively large blocks of data (21). Such large blocks storable in large address spaces are not always filled with meaningful data. To more efficiently use the data-storage space in the data- storage buffer, the allocatable unit or segment (28) of the data buffer is made smaller than the data capacity of the large block. Each time a large block of data (21) is to be written into the data buffer, a sufficient number of the segments (23, 25, 27) for storing data of one large block is allocated for receiving the data. After the data of the one block is written into the data buffer, the allocated segments are examined; all of the allocated segments not storing data (25, 27) from the one large block are deallocated. The invention is particularly useful for data buffers acting as cached data storage for large-capacity direct-access storage devices (DASD) (14) and are coupled to host processors (10) programmed to operate with such DASD. The procedure is followed for data written into the caching data storage whether supplied by DASD or the host processors.

Method and Apparatus for Cache Slot Allocation Based on Data Origination Location or Final Data Destination Location

Operational information in a storage system is collected regarding storage media storage tiers, devices, drives, tracks on drives, and logical storage layers, to determine an estimated amount of time it will take to write data from cache to the intended drive when a new write operation arrives at the storage system. This information is then used to decide which type of cache is most optimal to store the data for the write operation, based on the estimated amount of time it will take to write data out from the cache. By allocating cache slots from a faster cache to write operations that are expected to quickly be written out to memory, and allocating cache slots from the slower cache to write operations that are expected to take more time to be written out to memory, it is possible to increase the availability of the cache slots in the faster cache.

Integration of application indicated minimum time to cache for a two-tiered cache management mechanism

An indication is received from a host application of a first minimum retention time in a cache comprising a first type of memory and a second type of memory for a first plurality of tracks, wherein the first minimum retention time is not indicated for a second plurality of tracks. Based on the first minimum retention time, a second minimum retention time is set for the first plurality of tracks for the first type of memory and a third minimum retention time is set for the first plurality of tracks for the second type of memory. A track of the first plurality of tracks is demoted from the first type of memory, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the first type of memory and the track has been in the first type of memory for a time that exceeds the second minimum retention time.

Populating a first stride of tracks from a first cache to write to a second stride in a second cache

Provided are a computer program product, system, and method for managing data in a cache system comprising a first cache, a second cache, and a storage system. A determination is made of tracks stored in the storage system to demote from the first cache. A first stride is formed including the determined tracks to demote. A determination is made of a second stride in the second cache in which to include the tracks in the first stride. The tracks from the first stride are added to the second stride in the second cache. A determination is made of tracks in strides in the second cache to demote from the second cache. The determined tracks to demote from the second cache are demoted.

Providing track access reasons for track accesses resulting in the release of prefetched cache resources for the track

Provided are a computer program product, system, and method for providing track access reasons for track accesses resulting in the release of prefetched cache resources for the track. A first request for a track is received from a process for which prefetched cache resources to a cache are held for a second request for the track that is expected. A track access reason is provided for the first request specifying a reason for the first request. The prefetched cache resources are released before the second request to the track is received. Indication is made in an unexpected released track list of the track and the track access reason for the first request.

Using a machine learning module to dynamically determine tracks to prestage from storage to cache

Provided are a computer program product, system, and method for determining tracks to prestage into cache from a storage. Information is provided related to determining tracks to prestage from the storage to the cache in a stage group of sequential tracks including a trigger track comprising a track number in the stage group at which to start prestaging tracks and Input/Output (I/O) activity information to a machine learning module. A new trigger track in the stage group at which to start prestaging tracks is received from the machine learning module having processed the provided information. The trigger track is set to the new trigger track. Tracks are prestaged in response to processing an access request to the trigger track in the stage group.

Selective information caching on disk drive

A non-mechanical persistent storage is provided for a mechanical storage device. The operating system instructs the mechanical storage device to cache ranges of data stored in the mechanical storage device in the non-mechanical persistent storage. The mechanical storage device then transfers the data to the non-mechanical persistent storage. When the operating system makes a write to a range that is tracked in the non-mechanical persistent storage, the data is written to the mechanical storage and mirrored to the non-mechanical persistent storage. When the operating system makes a read to a range that is tracked in the non-mechanical persistent storage, such as when the system is in startup, the data is read from the non-mechanical persistent cache.

Increased destaging efficiency by smoothing destaging between current and desired number of destage tasks

Techniques for increased destaging efficiency by smoothing destaging tasks to reduce long input/output (I/O) read operations are described. A system may comprise a processor device operable in the computing storage environment. The processor device calculates a current number of the destaging tasks and calculates a desired number of the destaging tasks. The processor device smoothes the destaging of the of the destaging tasks between the desired number of the destaging tasks and the current number of the destaging tasks by accelerating the calculating of the current number of the destaging tasks and the desired number of the destaging tasks, according to either a time interval or a variable recomputed destaging task interval, for reaching the desired number of the destaging tasks by decrementing the current number of destaging tasks or incrementing the current number of destaging tasks.

Efficient processing of cache segment waiters

Various embodiments for cache management in a distributed computing storage environment are provided. In one embodiment, a processor device, for a plurality of input/output (I/O) operations, initiates a process, separate from a process responsible for data segment assembly, for waking a predetermined number of waiting I/O operations.

Resolving cache slot locking conflicts for remote replication

Cache slots on a storage system may be shared between entities processing write operations for logical storage unit (LSU) tracks and entities performing remote replication for write operations for the LSU tracks. If a new write operation is received on a first storage system (S1) for a track of an LSU (R1) when the cache slot mapped to the R1 track is locked by a process currently transmitting data of the cache slot to a second storage system (S2), a new cache slot may be allocated to the R1 track, the data of the original cache slot copied to the new cache slot, and the new write operation for the R1 track initiated on S1 using the new cache slot; while the data of the original cache slot is independently, and perhaps concurrently, transmitted to S2 to be replicated in R2, the LSU on S2 that is paired with R1.

Cache management method and cache device using sector set

Provided are a cache management method and a cache device using a sector set. The cache management method includes receiving a write request of predetermined data to be written to a predetermined sector of a storage device, from a host device; determining whether a cache memory is allocated to a sector set including the predetermined sector; selectively allocating the cache memory to the sector set based on the result of determination; and storing the data requested to be written into the cache memory allocated to the sector set. According to the present invention, access speed of a flash memory may be increased by writing data of a whole sector set at a time.

Tape drive with intelligent selection of wrap / track for temporarily storing flushed data

A tape drive that can select one or more wraps from any available wraps on a tape medium for writing temporary data upon detecting a flush condition. The one or more wraps selected for writing temporary data can be selected from wraps otherwise reserved for normal writing operations. Selection of the one or more wraps for temporary writing may be based on multiple considerations, including proximity to the wrap of current data writing operations and tape medium degradation. The one or more wraps selected for writing temporary data may be selected with or without regard of their assigned read/write direction. Assigning wraps based on proximity and/or degradation can lead to certain operational advantages including reducing tape write head movement in the transverse direction and spreading tape medium wear more evenly across the surface of the tape medium.

Access accelerator for active HBase database regions

In a method for improving performance of a database, create, in a memory, an instance of a segment of data corresponding to a segment of data in a database on a persistent file system. The segment of data in the database on the persistent file system is expected to experience a high plurality of reads and writes during a certain time period. Receive a request to modify the segment of data in the database on the persistent file system. Modify the instance of the segment of data in the memory.

Preemptive upgrade for full-span demotion

公开了一种用于改进到RAID阵列的降级性能的方法。该方法周期性地在高速缓存中扫描准备好被降级到RAID阵列的第一跨度。在扫描高速缓存时，该方法识别当前未准备好被降级到RAID阵列但在高速缓存的后续扫描期间将可能准备好被降级的第二跨度。该方法发起将第二跨度的任何缺失的数据从RAID阵列抢先升级到高速缓存中，以为后续扫描做准备。在发生后续扫描时，该方法从高速缓存将第二跨度从高速缓存降级到RAID阵列。

Wait classified cache writes in a data storage system

In one embodiment, a task control block (TCB) for allocating cache storage such as cache segments in a multi-track cache write operation may be enqueued in a wait queue for a relatively long wait period, the first time the task control block is used, and may be re-enqueued on the wait queue for a relatively short wait period, each time the task control block is used for allocating cache segments for subsequent cache writes of the remaining tracks of the multi-track cache write operation. As a result, time-out suspensions caused by throttling of host input-output operations to facilitate cache draining, may be reduced or eliminated. It is appreciated that wait classification of task control blocks in accordance with the present description may be applied to applications other than draining a cache. Other features and aspects may be realized, depending upon the particular application.

Determining an amount of data of a track to stage into cache using a machine learning module

Provided are a computer program product, system, and method for determining sectors of a track to stage into cache using a machine learning module. Performance attributes of system components affected by staging tracks from the storage to the cache are provided to a machine learning module. An output is received, from the machine learning module having processed the provided performance attributes, indicating a staging strategy indicating sectors of a track to stage into the cache comprising one of a plurality of staging strategies. Sectors of an accessed track that is not in the cache are staged into the cache according to the staging strategy indicated in the output.

Storage controlling system and storage controlling apparatus

A storage controlling system, coupled to a storage apparatus including storage disk devices, receives writing target data, generates a parity in units of parity generation of a given length for the data, and stores the data and parity into the devices. The system includes a cache memory and controller. The controller includes: a reception section receiving a writing instruction including the writing target data and information for specifying a target sector to write the data to; a decision section deciding whether processing target data is held in the cache memory, the processing target data including at least one unit of parity generation that includes sector data stored in the sector and fraction data other than the sector data; and a writing processing section updating, when the processing target data is in the cache memory, the data based on the instruction and outputting the post-update data as the writing target data to the apparatus.

Dynamically determining tracks to prestage from storage to cache using a machine learning module

Provided are a computer program product, system, and method for determining tracks to prestage into cache from a storage. Information is provided related to determining tracks to prestage from the storage to the cache in a stage group of sequential tracks including a trigger track comprising a track number in the stage group at which to start prestaging tracks and Input/Output (I/O) activity information to a machine learning module. A new trigger track in the stage group at which to start prestaging tracks is received from the machine learning module having processed the provided information. The trigger track is set to the new trigger track. Tracks are prestaged in response to processing an access request to the trigger track in the stage group.

Maintaining an active track data structure to determine active tracks in cache to process

Provided are a computer program product for managing tracks in a storage in a cache. An active track data structure indicates tracks in the cache that have an active status. An active bit in a cache control block for a track is set to indicate active for the track indicated as active in the active track data structure. In response to processing the cache control block, a determination is made, from the cache control block for the track, whether the track is active or inactive to determine processing for the cache control block.

書き込みセット内のトラックのためのキャッシュ・リソースが解放された後、書き込みセット内のトラックへの予想される書き込みのためにキャッシュ・リソースを取得する

キャッシュにキャッシュされたストレージ内のトラックへのホストからの書き込み要求のためにキャッシュ・リソースをプリフェッチするためのコンピュータ・プログラム製品、システム及び方法が提供される。書き込みセット内のトラックに対する予想される書き込みを受け取る前に、書き込みセット内の複数のトラックのために保持されるキャッシュ・リソースが解放される。書き込みセット内のトラックへの予想される書き込み要求に使用するために、キャッシュ・リソースの解放の後に、書き込みセット内のトラックのためのキャッシュ・リソースが取得される。

Using track locks and stride group locks to manage cache operations

Provided are a computer program product, system, and method for using track locks and stride group locks to manage cache operations. A group of tracks from the storage devices are stored in a cache. Exclusive track locks for tracks in the group in the cache are granted for writes to the tracks in the group in the cache, wherein exclusive track locks can be simultaneously held for writes to different tracks in the cache. An exclusive group lock for the group of tracks in the cache is granted to destage the tracks in the group from the cache to the storage devices. The exclusive group lock is released in response to completing the destage of the tracks in the group in the cache to the storage devices.

Maintaining an active track data structure to determine active tracks in cache to process

Provided are a computer program product for managing tracks in a storage in a cache. An active track data structure indicates tracks in the cache that have an active status. An active bit in a cache control block for a track is set to indicate active for the track indicated as active in the active track data structure. In response to processing the cache control block, a determination is made, from the cache control block for the track, whether the track is active or inactive to determine processing for the cache control block.

トラックのためにプリフェッチされたキャッシュ・リソースの開放をもたらす、トラック・アクセスについてのトラック・アクセス理由の提供

トラックのためにプリフェッチされたキャッシュ・リソースの開放をもたらす、トラック・アクセスについてのトラック・アクセス理由を提供するためのコンピュータ・プログラム製品、システム、および方法が提供される。キャッシュへプリフェッチされたキャッシュ・リソースが、予想されるトラックに関する第２の要求のために保持されている、そのトラックに関する第１の要求がプロセスから受信される。第１の要求についての理由を指定するトラック・アクセス理由が第１の要求について提供される。トラックへの第２の要求が受信される前に、プリフェッチされたキャッシュ・リソースが開放される。予想外に開放されたトラックのリスト中にトラック、および第１の要求についてのトラック・アクセス理由の表示が行われる。

Data management method for storage media

In one implementation, this disclosure provides a method for executing a partial band rewrite operation comprising identifying a first track of a shingled data band to receive data of a write received at a shingled media storage device and writing a first subset of the received data to a media cache, where the first subset corresponds to the first track of the shingled data band to receive data of the write command. The method also includes writing a remaining subset of the received data to target locations within the shingled data band without updating data on the first track within the shingled data band corresponding to the first subset of the received data.

Writing adjacent tracks to a stride, based on a comparison of a destaging of tracks to a defragmentation of the stride

Compressed data is maintained in a plurality of strides of a redundant array of independent disks, wherein a stride is configurable to store a plurality of tracks. A request is received to write one or more tracks. The one or more tracks are written to a selected stride of the plurality of strides, based on comparing the number of operations required to destage selected tracks from the selected stride to the number of operations required to defragment the compressed data in the selected stride.