Selektive Speicherplatzfreigabe eines Datenspeichers unter Verwendung von Vergleichs- und Verlagerungskennzahlen

Speicherplatz eines Datenspeichers eines Datenspeichersystems wird freigegeben durch Ermitteln von Vergleichskennzahlen von im Datenspeichersystem gespeicherten Daten; Ermitteln von Verlagerungskennzahlen, die sich auf ein Verlagern der Daten innerhalb des Datenspeichers beziehen; Ermitteln von Nutzenkennzahlen der Daten, welche die Vergleichskennzahlen mit den Verlagerungskennzahlen für die Daten verbinden; und Verfügbarmachen der Daten für die Speicherplatzfreigabe, deren Nutzenkennzahl eine Nutzenkennzahlgrenze nicht erreicht. Somit werden Daten, die andernfalls entfernt oder herabgestuft werden, die jedoch die Nutzenkennzahlgrenze erreichen oder überschreiten, von einer Speicherplatzfreigabe ausgenommen und stattdessen im Datenspeichersystem beibehalten.

Verwalten von Cachespeicher-Auslagerungsüberprüfungszeiten

Es werden Systeme und Verfahren zum Verwalten von Auslagerungsüberprüfungszeiten in einem Cachespeicher bereitgestellt. Ein System beinhaltet einen Cachespeicher und einen Prozessor. Der Prozessor ist dafür konfiguriert, einen ersten Thread zu verwenden, um fortlaufend eine gewünschte Überprüfungszeit für das Überprüfen der Mehrzahl von Speicherspuren in dem Cachespeicher zu ermitteln, und einen zweiten Thread zu verwenden, um fortlaufend eine tatsächliche Überprüfungszeit der Mehrzahl von Speicherspuren in dem Cachespeicher auf der Grundlage der fortlaufend ermittelten gewünschten Überprüfungszeit zu steuern. Ein Verfahren beinhaltet das Verwenden eines ersten Thread, um fortlaufend eine gewünschte Überprüfungszeit für das Überprüfen der Vielzahl von Speicherspuren in dem Cachespeicher zu ermitteln, und das Verwenden eines zweiten Thread, um fortlaufend eine tatsächliche Überprüfungszeit der Mehrzahl von Speicherspuren in dem Cachespeicher auf der Grundlage der fortlaufend ermittelten ...

Cache-Management von Spuren in einem ersten Cachespeicher und einem zweiten Cachespeicher für einen Speicher

Es werden ein Computerprogrammprodukt, ein System und ein Verfahren zum Cachespeicher-Management von Spuren in einem ersten Cachespeicher und einem zweiten Cachespeicher für einen Speicher bereitgestellt. Der erste Cachespeicher führt modifizierte und unmodifizierte Spuren in dem Speicher, der Eingabe/Ausgabe (E/A) Anforderungen unterliegt. Modifizierte und unmodifizierte Spuren werden von dem ersten Cachespeicher zurückgesetzt. Die von dem ersten Cachespeicher zurückgesetzten modifizierten und unmodifizierten Spuren werden an den zweiten Cachespeicher weitergegeben. Die von dem zweiten Cachespeicher zurückgesetzten modifizierten und unmodifizierten Spuren werden verworfen. Die modifizierten Spuren in dem zweiten Cachespeicher, die sich an naheliegenden physischen Orten auf der Speichereinheit befinden, werden gruppiert, und die gruppierten modifizierten Spuren werden von dem zweiten Cachespeicher an die Speichereinheit ausgelesen.

Dynamically adjusted threshold for population of secondary cache

The population of data to be inserted into secondary data storage cache is controlled by determining a heat metric of candidate data; adjusting a heat metric threshold; rejecting candidate data provided to the secondary data storage cache whose heat metric is less than the threshold; and admitting candidate data whose heat metric is equal to or greater than the heat metric threshold. The adjustment of the heat metric threshold is determined by comparing a reference metric related to hits of data most recently inserted into the secondary data storage cache, to a reference metric related to hits of data most recently evicted from the secondary data storage cache; if the most recently inserted reference metric is greater than the most recently evicted reference metric, decrementing the threshold; and if the most recently inserted reference metric is less than the most recently evicted reference metric, incrementing the threshold.

Cache management of tracks in a first cache and a second cache for a storage

Managing cache destage scan times

DIFFERENTIAL CACHING MECHANISM BASED ON MEDIA I/O SPEED, CAPABLE OF EFFICIENTLY ASSIGNING CACHE

PURPOSE: A differential caching mechanism based on media i/o speed is provided to increase the hit rate of storage units by efficiently assigning cache. CONSTITUTION: A cache entry related to high-speed response storage units and cache entry related to slow response storage units are saved in the read cache(316). An extracting method is prepared in the read cache. The extracting method downward controls the cache entries of fast response storage devices. The high and low read hit ratio is calculated by the read hit times through the interval. COPYRIGHT KIPO 2011 ...

Apparatus, system, and method for emergency backup

An apparatus, system, and method quickly backs up data in an emergency situation and reduces battery backup dependence. The apparatus may include a backup module and a dedicated computer readable storage device. The backup module interfaces with system memory and selectively transmits modified data to the storage device in response to a detected system failure. The dedicated storage device stores the modified data around the outer edge of a hard disk in order to increase write performance. The system may include the backup module, the storage device, a plurality of client devices, and a plurality of storage devices. The method includes storing modified and unmodified data, detecting a system failure, and transmitting modified data stored in a memory module to a dedicated computer readable backup device. Upon rebooting the device, the method may include restoring the modified data to the system memory and destaging the modified data to the plurality of storage devices.

PREFERENTIAL CPU UTILIZATION FOR TASKS

A set of like tasks to be performed is organized into a first group. Upon a determined imbalance between dispatch queue depths greater than a predetermined threshold, the set of like tasks is reassigned to an additional group.

NONSYNCHRONOUS CHANNEL/DASD COMMUNICATION SYSTEM

A control unit for DASD operation to transfer data between the device and a buffer and between a channel and a buffer. In that manner the channel and device are enabled to transfer data independently of each other. Mechanisms are provided for communication between the channel interface process in the control unit and the device interface process in the control unit. Some of these mechanisms are stored with the record in the buffer and others are stored in control storage. Principle communicating mechanisms include a device record pointer, a channel record pointer, a next operation field, a device state indicator, record control flags, and two buffer pointers.

Cache management of tracks in first cache and second cache for storage

Provided are a computer program product, a system, and a method for cache management of tracks in a first cache and a second cache for a storage. The first cache maintains modified and unmodified tracks in the storage subject to input/output (I/O) requests. Modified and unmodified tracks are demoted from the first cache. The modified and the unmodified tracks demoted from the first cache are promoted to the second cache. The unmodified tracks demoted from the second cache are discarded. The modified tracks in the second cache that are at proximate physical locations on the storage device are grouped and the grouped modified tracks are destaged from the second cache to the storage device.

NONSYNCHRONOUS DASD CONTROL

Apparatus for controlling DASD in a manner that is not synchronous with channel operation, that is, transfer of commands and data are not limited to inter-record gap periods. A device interface processor controls which recording track is accessed by the DASD with data being transferred to and from a buffer. A device track indicator designates which recording tracks the device will move to in sequence. A channel interface processor controls the movement of data from and to the buffer and channel. A channel track indicator designates the recording track sequence in which the channel interface processor will access the data to be transferred. A method of operation is disclosed for utilizing the two indicators to enable the device and channel processors to communicate with each other in case the device reads incorrect records in a multi-track read operation.

Method and system for using multiple data structures to manage data in cache

Wear leveling of solid state disks distributed in a plurality of redundant array of independent disk ranks

A computational device allocates a plurality of solid state disks to a plurality of redundant array of independent disk (RAID) ranks, wherein a different solid state disk is absent in each RAID rank of the plurality of RAID ranks. The computational device determines at least one selected solid state disk from the plurality of solid state disks, wherein the at least one selected solid state disk is estimated to have undergone a greater amount of wear in comparison to other solid state disks in the plurality of solid state disks. Relatively more data and parity information is written to those RAID ranks in which the at least one selected solid state disk is absent in comparison to those RAID ranks in which the at least one selected solid state disk is present.

Vorabladen von Datenspuren und Paritätsdaten zur Verwendung zum Auslagern aktualisierter Spuren

Computerprogrammprodukt zum Verarbeiten einer Gruppe von Datenspuren und Paritätsdaten, die mindestens einer Speichereinheit (100) mit sequenziellem Zugriff zugehörig sind und mit einer ersten Cache-Einheit (14) und einer zweiten Cache-Einheit (18) Daten austauschen, wobei das Computerprogrammprodukt ein durch einen Computer lesbares Speichermedium aufweist, auf dem ein durch einen Computer lesbarer Programmcode enthalten ist, der ausgeführt wird, um Arbeitsschritte durchzuführen, wobei die Arbeitsschritte aufweisen:Empfangen (300) einer Schreibanforderung, die mindestens eine aktualisierte Spur für die Gruppe von Spuren enthält;Speichern (302) der mindestens einen aktualisierten Spur unter Verwendung der ersten Cache-Einheit (14);Senden einer Anforderung zum Vorabladen an die mindestens eine Speichereinheit (100) mit sequenziellem Zugriff, um der Gruppe von Spuren zugehörige Spuren vorab in die zweite Cache-Einheit (18) zu laden;Erzeugen (308) einer Leseanforderung, um die vorab geladenen ...

Write data error checking in a PCI Bus system

In a PCI bus system, a method and system check for errors in rite data transferred from a PCI data source across a PCI bus to the PCI bus system, the data comprising a plurality of blocks. Redundancy calculation logic receives the write data across the PCI bus, calculates a check value for each block of the data transferred across the PCI bus, and updating any previously calculated check value with the calculated check value at a storage location of a storage memory. Data path logic is coupled to the PCI bus and to the storage memory, and responds to a unique identifier of a redundancy write command sent subsequent to completion of the transfer of the write data across the PCI interface. The data path logic responds to the write command unique identifier, detecting the updated calculated check value at the storage location of the storage memory. Error check logic coupled to the data path logic determines whether the detected updated calculated check value indicates an error, and upon the ...

Method, system, and program for an adaptor to read and write to system memory

Provided are a method, system, and program for an adaptor to read and write to system memory. A plurality of blocks of data to write to storage are received at an adaptor. The blocks of data are added to a buffer in the adaptor. A determination is made of pages in a memory device and I/O requests are generated to write the blocks in the buffer to the determined pages, wherein two I/O requests are generated to write to one block split between two pages in the memory device. The adaptor executes the generated I/O requests to write the blocks in the buffer to the determined pages in the memory device.

Intelligent write caching for sequential tracks

In a computing storage environment for destaging data from nonvolatile storage (NVS) to a storage unit, write caching for sequential tracks by a processor device is provided. When a first track is determined to be sequential, and an earlier track is also determined to be sequential, a temporal bit associated with the earlier track is cleared to allow for destage of data of the earlier track. If a temporal bit for one of a plurality of additional tracks in one of a plurality of strides in a modified cache is determined to be not set, a stride associated with the one of the plurality of additional tracks is selected for a destage operation. If the NVS exceeds a predetermined storage threshold, a predetermined one of the plurality of strides is selected for the destage operation.

Indication of a destructive write via a notification from a disk drive that emulates blocks of a first block size within blocks of a second block size

A disk drive receives a request to write at least one block of a first block size, wherein the disk drive is configured to store blocks of a second block size that is larger in size than the first block size, and wherein the disk drive stores via emulation a plurality of emulated blocks of the first block size in each block of the second block size. The disk drive generates a read error, in response to reading a selected block of the second block size in which the at least block of the first block size is to be written via the emulation. The disk drive performs a destructive write of selected emulated blocks of the first block size that caused the read error to be generated. The disk drive writes the at least one block of the first block size in the selected block of the second block size. The disk drive sends a notification to indicate the performing of the destructive write.

Method for dual agent processes and dual active server processes

Disclosed is a method, system, and program for task processing and monitoring of configuration and state information. A first server process and a second server process are detected. A first agent process is registered with the first server process. A second agent process is registered with the second server process. When a task is to be executed by the first server process, the task is executed with the first agent process. When the task is to be executed by the second server process, the task is executed with the second agent process.

Adaptive cache promotions in a two level caching System

Provided are a computer program product, system, and method for managing data in a first cache and a second cache. A reference count is maintained in the second cache for the page when the page is stored in the second cache. It is determined that the page is to be promoted from the second cache to the first cache. In response to determining that the reference count is greater than zero, the page is added to a Least Recently Used (LRU) end of an LRU list in the first cache. In response to determining that the reference count is less than or equal to zero, the page is added to a Most Recently Used (MRU) end of the LRU list in the first cache.

Adjustment of destage rate based on read and write response time requirements

A storage controller that includes a cache receives a command from a host, wherein a set of criteria corresponding to read and write response times for executing the command have to be satisfied. The storage controller determines ranks of a first type and ranks of a second type corresponding to a plurality of volumes coupled to the storage controller, wherein the command is to be executed with respect to the ranks of the first type. Destage rate corresponding to the ranks of the first type are adjusted to be less than a default destage rate corresponding to the ranks of the second type, wherein the set of criteria corresponding to the read and write response times for executing the command are satisfied.

Verfahren und System um Daten in einem Datenverarbeitungssystem zu suchen

Löschen von Relationen zwischen Quellen und platzsparenden Zielen in Architekturen mit mehreren Zielen

Es wird ein Verfahren zum Löschen einer Relation zwischen einer Quelle und einem Ziel in einer Architektur mit mehreren Zielen beschrieben. Die Architektur mit mehreren Zielen beinhaltet eine Quelle und mehrere platzsparende (SE-)Ziele, die dieser zugeordnet sind. Bei einer Ausführungsform beinhaltet ein solches Verfahren zunächst ein Identifizieren einer Relation, die aus der Architektur mit mehreren Zielen gelöscht werden soll. Anschließend wird ein platzsparendes (SE-)Ziel identifiziert, das der Relation zugehörig ist. Eine Zuordnungsstruktur ordnet Daten in logischen Spuren des SE-Ziels physischen Spuren einer Datenablage zu. Anschließend identifiziert das Verfahren ein gleichgeordnetes SE-Ziel, das Daten von dem SE-Ziel erbt. Nachdem das SE-Ziel und das gleichgeordnete SE-Ziel identifiziert worden sind, modifiziert das Verfahren die Zuordnungsstruktur, um die Daten in den physischen Spuren der Datenablage den logischen Spuren des gleichgeordneten SE-Ziels zuzuordnen. Die Relation wird ...

Asynchrone DASD-Steuerung

Management of partial data segments in dual cache systems

Integrating a flash cache into large storage systems

An I/O enclosure module is provided with one or more I/O enclosures having a plurality of slots for receiving electronic devices. A host adapter is connected a first slot of the I/O enclosure module and is configured to connect a host to the I/O enclosure. A device adapter is connected to a second slot of the I/O enclosure module and is configured to connect a storage device to the I/O enclosure module. A flash cache is connected to a third slot of the I/O enclosure module and includes a flash-based memory configured to cache data associated with data requests handled through the I/O enclosure module. A primary processor complex manages data requests handled through the I/O enclosure module by communicating with the host adapter, device adapter, and flash cache to manage to the data requests.

Cache management of tracks in a first cache and a second cache for a storage

Provided a computer program product, system, and method for cache management of tracks in a first cache and a second cache for a storage. The first cache maintains modified and unmodified tracks in the storage subject to Input/Output (I/O) requests. Modified and unmodified tracks are demoted from the first cache. The modified and the unmodified tracks demoted from the first cache are promoted to the second cache. The unmodified tracks demoted from the second cache are discarded. The modified tracks in the second cache that are at proximate physical locations on the storage device are grouped and the grouped modified tracks are destaged from the second cache to the storage device.

MANAGING HIGH SPEED SLOW ACCESS CHANNEL TO SLOW SPEED CYCLIC SYSTEM DATA TRANSFERS

A cached DASD controller is illustrated which is attached to a high speed serial channel, such as an optical fiber channel. The data rate of the serial channel is much greater than the data rate of a DASD connected to the controller. The serial channel has a relatively long propagation time such that synchronous operations between the host processor 10 and the DASD cannot be efficiently performed. Operation of a data transfer, whether read or write between the host processor 10 and the DASD is monitored. Whenever a copy of the track contents and in cache and the DASD reaches either an index mark with or a break point from a roll mode operation or certain write operations occur resulting in predetermined data being stored in cache, then a GOCACHE flag is set in a control portion of the controller. The device operations are then momentarily idled while cache to host processor operations are enabled.

Apparatus, system, and method for storing and retrieving compressed data

An apparatus, system, and method are disclosed for storing and retrieving compressed data. A compression module compresses a data file organized in logical tracks. A ratio module determines a track compression ratio. The track compression ratio is a ratio of an integer value n to one. A destage module destages a single directory entry for the data file to a directory. The directory entry points to a zeroth track on a hard disk drive. The destage module further destages the data file sequentially to tracks of the hard disk drive from the zeroth track with n logical tracks of the data file stored on one physical track of the hard disk drive. A stage module stages a kth logical track from a physical track of the hard disk drive. The physical track is specified by an integer value of k divided by n.

Method and system for recovery of meta data in a storage controller

Disclosed is a method, system, and article of manufacture for processing modified meta data for data recovery operations. The meta data provides information on user data maintained in a storage device. The system determines whether meta data tracks maintained in a cache were modified and indicates in a non-volatile memory that the determined meta data tracks were modified. Data recovery operations may be initiated as a result of a system failure, such as a warmstart or coldstart recovery. During such data recovery operations, the system processes the non-volatile memory and the indications of modified meta data tracks therein to rebuild lost meta data tracks in the cache.

Cachen von Daten in einem Speichersystem mit mehreren Cache-Speichern

Es werden ein Computerprogrammprodukt, ein System und ein Verfahren zum Verwenden eines Attributes einer Schreibanforderung bereitgestellt, um zu ermitteln, wo Daten in einem Speichersystem mit mehreren Cachespeichern einschließlich eines nichtflüchtigen Cachespeichers in einer Speichereinheit mit sequenziellem Zugriff gecacht werden sollen. In Reaktion auf das Feststellen, dass modifizierte Spuren gecacht werden sollen, werden empfangene modifizierte Spuren in der nichtflüchtigen Speichereinheit zwischengespeichert, die in der Speichereinheit mit sequenziellem Zugriff integriert ist. Es wird eine Schreibanforderung mit modifizierten Spuren empfangen. Es wird ein Ermitteln dahingehend durchgeführt, ob ein Attribut der empfangenen Schreibanforderung eine Bedingung erfüllt. In Reaktion auf das Ermitteln, dass das ermittelte Attribut die Bedingung nicht erfüllt, werden die empfangenen modifizierten Spuren für die Schreibanforderung in der nichtflüchtigen Speichereinheit zwischengespeichert ...

Asynchrone DASD-Steuerung

A STORAGE SUBSYSTEM WITH HASHED CACHE ADDRESSING

Caching data in a storage system having multiple caches

Provided are a computer program product, system, and method for using an attribute of a write request to determine where to cache data in a storage system having multiple caches including non-volatile storage cache in a sequential access storage device. Received modified tracks are cached in the non- volatile storage device integrated with the sequential access storage device in response to determining to cache the modified tracks. A write request having modified tracks is received. A determination is made as to whether an attribute of the received write request satisfies a condition. The received modified tracks for the write request are cached in the non- volatile storage device in response to determining that the determined attribute does not satisfy the condition. A destage request is added to a request queue for the received write request having the determined attribute not satisfying the condition.

Managing cache destage scan times

Systems and methods for managing destage scan times in a cache are provided. One system includes a cache and a processor. The processor is configured to utilize a first thread to continually determine a desired scan time for scanning the plurality of storage tracks in the cache and utilize a second thread to continually control an actual scan time of the plurality of storage tracks in the cache based on the continually determined desired scan time. One method includes utilizing a first thread to continually determine a desired scan time for scanning the plurality of storage tracks in the cache and utilizing a second thread to continually control an actual scan time of the plurality of storage tracks in the cache based on the continually determined desired scan time. Physical computer storage mediums including a computer program product for performing the above method are also provided.

Writing further new data in a raid array that stores data and parity in a different block size

A Redundant Array of Independent Disks (RAID) controller receives new data that is to be written, wherein the new data is indicated in blocks of a first block size. The RAID controller reads old data, and old parity that corresponds to the old data, stored in blocks of a second block size that is larger in size than the first block size. The RAID controller computes new parity based on the new data, the old data, and the old parity. The RAID controller writes the new data and. the new parity aligned to the blocks of the second block size, wherein 'portions of the old data that are not overwritten by the RATD controller are also written to the blocks of the second block size. This allows efficient writing and storage of 512 byte blocks in newer disks with 4 Kilobyte block memory spaces.

Method and system for selective space reclamation of data storage memory employing heat and relocation metrics

A method and computer program product for reclaiming space of a data storage memory of a data storage memory system, and a computer-implemented data storage memory system are provided. The method includes: determining heat metrics of data stored in the data storage memory; determining relocation metrics related to relocation of the data within the data storage memory; determining utility metrics of the data relating the heat metrics to the relocation metrics for the data; and making the data whose utility metric fails a utility metric threshold, available for space reclamation. Thus, data that otherwise may be evicted or demoted, but that meets or exceeds the utility metric threshold, is exempted from space reclamation and is instead maintained in the data storage memory.

Apparatus, system, and method for error checking and recovery of transmitted data in a SCSI environment

An apparatus, system, and method are disclosed for data error checking and recovery in a data storage device. A redundancy check module creates a redundancy check for data on a data storage device in a SCSI End-to-End Checking Standard environment and a redundancy check storage module stores the redundancy check in a guard associated with the data.

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).

Cache-Management von Spuren in einem ersten Cachespeicher und einem zweiten Cachespeicher für einen Speicher

Computerprogrammprodukt zum Verwalten von Daten in einem Cachespeichersystem, aufweisend einen ersten Cachespeicher, einen zweiten Cachespeicher und eine Speichereinheit, wobei das Computerprogrammprodukt ein computerlesbares Speichermedium mit einem darauf ausgebildeten computerlesbaren Programmcode aufweist, der ausgeführt wird, um Operationen durchzuführen, wobei die Operationen aufweisen:Führen in dem ersten Cachespeicher modifizierter und unmodifizierter Spuren in dem Speicher, der Eingabe/Ausgabeanforderungen unterliegt;Zurücksetzen modifizierter und unmodifizierter Spuren von dem ersten Cachespeicher;Weitergeben der von dem ersten Cachespeicher zurückgesetzten modifizierten und unmodifizierten Spuren an den zweiten Cachespeicher;Verwerfen unmodifizierter Spuren, die von dem zweiten Cachespeicher zurückgesetzt wurden;Gruppieren modifizierter Spuren in dem zweiten Cachespeicher, die sich an nahen physischen Orten auf der Speichereinheit befinden; undAuslesen der gruppierten modifizierten ...

Demoting partial tracks from a first cache to a second cache

Indication of a destructive write via a notification from a disk drive that emulates blocks of a first block size within blocks of a second block size

Promotion of partial data segments in flash cache

Error handling between a processor and a system managed by the processor

Disclosed is a system for handling errors. A system managed by a processor processes an error in the system. The system then generates an interrupt to the processor indicating that an error occurred and executes an error mode before the processor interprets the interrupt. As part of the error mode, the system prevents data from transferring between the system and the processor and processes a read request from the processor to the system by returning data to the processor unrelated to the requested data. The processor would then process the interrupt indicating the error and execute a diagnostic mode to diagnose the error in the system.

Method, system, and program for performing read operations during a destage operation

Disclosed is a method, system, and program for processing data access requests, such as read requests, to a storage location maintained in both a first storage, such as a cache, area and second storage area, such as a disk drive, during a destage operation. A destage operation is granted access to the storage location to destage data from the storage location in the first storage area to the second storage area. During the destage operation, a data access request is granted access to the storage location.

Dynamically adjusted threshold for population of secondary cache

The population of data to be inserted into secondary data storage cache is controlled by determining a heat metric of candidate data; rejecting candidate data which is provided to the secondary data storage cache and whose heat metric is less than the threshold; and admitting candidate data whose heat metric is equal to or greater than the heat metric threshold. The adjustment of the heat metric threshold is determined by comparing a reference metric related to hits of data most recently inserted into the secondary data storage cache, to a reference metric related to hits of data most recently evicted from the secondary data storage cache; if the most recently inserted reference metric is greater than the most recently evicted reference metric, decrementing the threshold; and if the most recently inserted reference metric is less than the most recently evicted reference metric, incrementing the threshold.

Grouping and dispatching scans in cache

A method, system, and computer program product for grouping and dispatching scans in a cache directory of a processing environment is provided. A plurality of scan tasks is aggregated from a scan wait queue into a scan task queue. The plurality of scan tasks is determined by selecting one of (1) each of the plurality of scan tasks on the scan wait queue, (2) a predetermined number of the plurality of scan tasks on the scan wait queue, and (3) a set of scan tasks of a similar type on the scan wait queue. A first scan task from the plurality of scan tasks is selected from the scan task queue. The scan task is performed.

Resource allocation unit queue

Provided is a method, system, deployment and program for resource allocation unit queuing in which an allocation unit associated with a task is classified. An allocation unit freed as the task ends is queued for use by another task in a queue at a selected location within the queue in accordance with the classification of said allocation unit. In one embodiment, an allocation unit is queued at a first end of the queue if classified in a first class and is queued at a second end of the queue if classified in said second class. Other embodiments are described and claimed.

Apparatus and method to reconfigure a storage array disposed in a data storage system

A method is disclosed to reconfigure a storage array disposed in a data storage system. The method supplies a data storage system comprising a plurality of data storage devices, wherein each of the plurality of data storage devices is assigned to one of a plurality of data storage arrays, or is assigned as a spare device. The method then detects an unassigned data storage device, and determines if any of the plurality of data storage arrays comprises a degraded data storage array. If the method determines that any of the plurality of data storage arrays comprises a degraded data storage array, then the method determines if the unassigned data storage device can be used to restore the degraded data storage array to optimal reliability, optimal performance, and optimal efficiency. If the method determines that the unassigned data storage device can be used restore the degraded array to an array comprising optimal reliability, optimal performance, and optimal efficiency, then the method reconfigures ...

DETERMINING WHETHER TO USE A REPOSITORY TO STORE DATA UPDATED DURING A RESYNCHRONIZATION

Provided are a method, system, and article of manufacture for determining whether to use a repository to store data updated during a resynchronization. Writes to a primary storage are transferred to a secondary storage. A logical copy of the secondary storage as of a point-in-time is established. Writes to the secondary storage in the logical copy received from the primary storage during a logical copy duration after the point-in-time are stored in a repository that comprises less storage space than the secondary storage in the logical copy. The transferring of writes to the secondary storage is suspended. During the suspension writes to the primary storage are indicated in an out-of-synch data structure. A determination is made as to as to whether available storage space in the repository is sufficient to store writes transferred from the secondary storage while transferring the writes from the out-of-synch data structure in response to ending the suspension of the transferring of writes ...

Writing of new data of a first block size in a raid array that stores both parity and data in a second block size

A Redundant Array of Independent Disks (RAID) controller receives new data that is to be written, wherein the new data is indicated in blocks of a first block size. The RAID controller reads old data, and old parity that corresponds to the old data, stored in blocks of a second block size that is larger in size than the first block size. The RAID controller computes new parity based on the new data, the old data, and the old parity. The RAID controller writes the new data and the new parity aligned to the blocks of the second block size, wherein portions of the old data that are not overwritten by the RAID controller are also written to the blocks of the second block size.

Deleting relations between sources and space-efficient targets in multi-target architectures

A method for deleting a relation between a source and a target in a multi-target architecture is described. The multi-target architecture includes a source and multiple space-efficient (SE) targets mapped thereto. In one embodiment, such a method includes initially identifying a relation for deletion from the multi-target architecture. A space-efficient (SE) target associated with the relation is then identified. A mapping structure maps data in logical tracks of the SE target to physical tracks of a repository. The method then identifies a sibling SE target that inherits data from the SE target. Once the SE target and the sibling SE target are identified, the method modifies the mapping structure to map the data in the physical tracks of the repository to the logical tracks of the sibling SE target. The relation is then deleted between the source and the SE target. A corresponding computer program product is also described herein.

APPARATUS FOR HASHING CACHE ADDRESSES IN A CACHED DISK STORAGE SYSTEM

Apparatus, system, and method for time sensitive copy

WEAR LEVELING OF SOLID STATE DISKS DISTRIBUTED IN A PLURALITY OF REDUNDANT ARRAY OF INDEPENDENT DISK RANKS

PURPOSE: Wear leveling of solid state disks distributed in a plurality of redundant array of independent disk ranks is provided to first allocate a spare space to SSDs with more abrasion than other SSDs, thereby realizing distributed sparing. CONSTITUTION: A plurality of SSD(Solid State Disks)s(102a~102n) are allocated to RAID(Redundant Array of Independent Disks) ranks(104a~104m) by an operation device(100). At least one selected SSD is determined by the operation device. Relatively more data and parity information are recorded in RAID ranks in which at least one selected SSD is lost by the operation device. COPYRIGHT KIPO 2011 ...

APPARATUS FOR HASHING CACHE ADDRESSES IN A CACHED DISK STORAGE SYSTEM

Method, system, and program for transferring data directed to virtual memory addresses to a device memory

Provided are a method, system, and program for transferring data directed to virtual memory addresses to a device memory. Indicator bits are set for ranges of device memory addresses in a device accessible over an Input/Output (I/O) bus indicating whether gathering is enabled for the device memory address ranges. Transfer operations are processed to transfer data to contiguous device memory addresses in the device. A determination is made as to whether the indicator bits for the contiguous device memory addresses indicate that gathering is enabled. A single bus I/O transaction is generated to transfer data for the contiguous device memory addresses over the I/O bus in response to determining that the indicator bits for the contiguous device memory addresses indicate that gathering is enabled.

Apparatus, system, and method for error checking and recovery of transmitted data in a SCSI environment

An apparatus, system, and method are disclosed for data error checking and recovery in a data storage device. A redundancy check module creates a redundancy check for data on a data storage device in a SCSI End-to-End Checking Standard environment and a redundancy check storage module stores the redundancy check in a guard associated with the data.

Method and system for maintaining information about modified data in cache in a storage system for use during a system failure

Disclosed is a system and method for caching data. A processor receives data from a host to modify a track in a first storage device. The processor stores a copy of the modified data in a cache and indicates in a second storage device the tracks for which there is modified data in cache. During data recovery operations, the processor processes the second storage device and data therein to determine the tracks for which there was modified data in cache. The processor then marks the determined tracks as failed to prevent data at the determined tracks in the first storage device from being returned in response to a read request until the failure is resolved. In further embodiments, in response to detecting a partial failure within the storage system, the processor would scan the cache to determine tracks for which there is modified data stored in the cache. The processor then stores in the second storage device information indicating the tracks having modified data in cache and schedules the ...

Cachen von Daten in einem Speichersystem mit mehreren Cache-Speichern

Computerprogrammprodukt zum Verwalten von Daten in einer Speichereinheit (4, 10; 100) mit sequenziellem Zugriff, die Leseanforderungen und Schreibanforderungen von einem System (2a, 2b...2n) in Bezug auf Spuren empfängt, die auf einem Speichermedium (114) mit sequenziellem Zugriff gespeichert sind, wobei das Computerprogrammprodukt aufweist ein computerlesbares Speichermedium mit einem darauf ausgebildeten computerlesbaren Programmcode, der ausgeführt wird, um Operationen durchzuführen, wobei die Operationen aufweisen:Cachen empfangener modifizierter Spuren in einer nichtflüchtigen Speichereinheit (104), die in der Speichereinheit (100) mit sequenziellem Zugriff integriert ist, in Reaktion auf Feststellen, dass modifizierte Spuren gecacht werden sollen;Empfangen (500) einer Schreibanforderung mit modifizierten Spuren;Ermitteln (502), ob ein Attribut der empfangenen Schreibanforderung eine Bedingung erfüllt;Cachen (508) der empfangenen modifizierten Spuren für die Schreibanforderung in der ...

Control method for incoming request waiting loop in client-server network has each request inserted in waiting loop entry corresponding to request priority plane

The control method has each incoming input/output request inserted in an entry in the waiting loop data structure (8) corresponding to the request priority plane, each entry having a number of requests of similar priority arranged in sequence, with processing of the requests held in the waiting loop in order of priority. Also included are Independent claims for the following: (a) a control system for an incoming request waiting loop; (b) a computer program product for an incoming request waiting loop control procedure; (c) a memory device with a request waiting loop data structure.

APPARATUS, SYSTEM, AND METHOD FOR SELECTING A SPACE EFFICIENT REPOSITORY

An apparatus, system, and method are disclosed for selecting a space efficient repository. A cache receives write data. A destage module destages the data sequentially to a coarse grained repository such as a stride level repository and destages a directory entry for the data to a coarse grained directory such as a stride level directory if the data satisfies a repository policy. In addition, the destage module destages the data to a fine grained repository such as a track level repository overwriting an existing data instance and destages the directory entry to a fine grained directory such as a track level directory if the data does not satisfy the repository policy.

METHOD AND SYSTEM FOR SETTING STORAGE DEVICE AND PRODUCT

(57)【要約】 【課題】 接続された記憶装置を記憶装置アダプタを介 して設定するための方法、システム、及びプログラムを 提供。 【解決手段】 記憶装置アダプタは、システムによる使 用のために記憶装置に記憶空間を追加する際に、記憶装 置への書き込みのための初期化データを生成する初期化 ルーチンを有する。要求を受信することで、システムに 対して記憶空間を追加する。命令は、記憶装置アダプタ による初期化ルーチンの実行を禁止することが可能な記 憶装置アダプタに対して送信される。記憶空間のための 初期化データが生成され、さらに記憶空間を初期化する ために前記記憶空間に対する書き込みのために、記憶装 置アダプタに対して初期化データが送信される。

Using different algorithms to destage different types of data from cache

Provided are a method, system, and article of manufacture for using different algorithms to destage different types of data from cache. A first destaging algorithm is used to destage a first type of data to a storage for a first duration. A second destaging algorithm is used to destage a second type of data to the storage for a second duration.

Resource allocation unit queue

Provided is a system, deployment and program for resource allocation unit queuing in which an allocation unit associated with a task is classified. An allocation unit freed as the task ends is queued for use by another task in a queue at a selected location within the queue in accordance with the classification of said allocation unit. In one embodiment, an allocation unit is queued at a first end of the queue if classified in a first class and is queued at a second end of the queue if classified in said second class. Other embodiments are described and claimed.

Periodische Auslagerung von Innen- und Aussendurchmessern von Platten zum Verbessern von Lesereaktionszeiten

Eine Speichersteuereinheit (102), die einen Cachespeicher (108) enthält, empfängt einen Befehl von einem Host (104a, 104b, ... 104n), wobei ein Satz von Kriterien, die Lesereaktionszeiten zum Ausführen des Befehls entsprechen, erfüllt sein muss (402). Eine Auslagerungsanwendung wird ausgeführt, die Spuren auf der Grundlage einer jüngsten Verwendung und eines räumlichen Ortes der Spuren auslagert, wobei eine räumliche Ordnung der Spuren in einer Datenstruktur unterhalten wird und die Auslagerungsanwendung die räumliche Ordnung der Spuren durchgeht (404). Spuren werden von zumindest Innen- oder Außendurchmessern von Platten in periodischen Intervallen ausgelagert, wobei die räumliche Ordnung der Spuren durchgegangen wird, wobei der Satz von Kriterien, die den Lesereaktionszeiten zum Ausführen des Befehls entsprechen, erfüllt wird (406). A memory control unit (102), which contains a cache memory (108), receives a command from a host (104a, 104b, ... 104n), whereby a set of criteria corresponding to read response times for executing the command must be met (402 ). A swap application is executed that swaps out tracks based on recent usage and spatial location of the tracks, a spatial order of the tracks is maintained in a data structure and the swap application iterates over the spatial order of the tracks (404). Tracks are swapped from at least inside or outside diameters of disks at periodic intervals, the spatial order of the tracks being traversed, meeting the set of criteria corresponding to the read response times for executing the instruction (406).

Vorabladen von Datenspuren und Paritätsdaten zur Verwendung zum Auslagern aktualisierter Spuren

Es werden ein Computerprogrammprodukt, ein System und ein Verfahren zum Vorabladen von Datenspuren und Paritätsdaten zur Verwendung zum Auslagern aktualisierter Spuren bereitgestellt. Es wird eine Schreibanforderung empfangen, die mindestens eine aktualisierte Spur für die Gruppe von Spuren enthält. Die mindestens eine aktualisierte Spur wird in einer ersten Cache-Einheit gespeichert. An die mindestens eine Speichereinheit mit sequenziellem Zugriff wird eine Anforderung zum Vorabladen gesendet, um Spuren aus der Gruppe von Spuren vorab in eine zweite Cache-Einheit zu laden. Es wird eine Leseanforderung erzeugt, um die vorab geladenen Spuren nach dem Senden der Anforderung zum Vorabladen zu lesen. Die der Leseanforderung von der zweiten Cache-Einheit zurückgesendeten gelesenen vorab geladenen Spuren werden in der ersten Cache-Einheit gespeichert. Aus der mindestens einen aktualisierten Spur und den gelesenen vorab geladenen Spuren werden neue Paritätsdaten berechnet.

Prefetching data tracks and parity data to use for destaging updated tracks

Provided are a computer program product, a system, and a method for prefetching data tracks and parity data so as to destage updated tracks. A write request is received comprising at least one updated track to the group of tracks. The at least one updated track is stored in a first cache device. A prefetch request is sent to the at least one sequential access storage device to prefetch tracks in the group of tracks to a second cache device. A read request is generated to read the prefetch tracks following the sending of the prefetch request. The read prefetch tracks returned to the read request from the second cache device are stored in the first cache device. New parity data is calculated from the at least one updated track and the read prefetch tracks.

Method, system, and program for caching data in a storage controller

Provided is a method, system, and program for caching updates to one target storage device in a first and second memories, wherein the target storage device is one of a plurality of storage devices. A determination is made of an allocation of available space in the second memory to the storage devices, wherein a total of the allocation of the available space to all the storage devices exceeds one hundred percent of the available space in the second memory. An update to one target storage device is received and then a determination is made as to whether adding the update to the second memory will exceed the allocation of available space for the target storage device in the second memory. One copy of the update is written to the second memory if adding the update to the second memory will not exceed the allocation of available space for the target storage device.

Anpassung der Auslagerungsgeschwindigkeit auf Grundlage von Anforderungen an Lese- und Schreib-Antwortzeiten

Eine Speichersteuereinheit, die einen Cache-Zwischenspeicher aufweist, empfängt einen Befehl von einem Host, wobei ein Satz von Kriterien, die den Lese- und Schreib-Antwortzeiten zum Ausführen des Befehls entsprechen, erfüllt sein muss; Die Speichersteuereinheit ermittelt Ränge eines ersten Typs und Ränge eines zweiten Typs, die einer Mehrzahl von Datenträgern entsprechen, die mit der Speichersteuereinheit verbunden sind, wobei der Befehl unter Berücksichtigung der Ränge des ersten Typs auszuführen ist. Die Auslagerungsgeschwindigkeit, die den Rängen des ersten Typs entspricht, wird so angepasst, dass sie geringer als eine Standard-Auslagerungsgeschwindigkeit ist, die den Rängen des zweiten Typs entspricht, wobei die Menge von Kriterien, die den Lese- und Schreib-Antwortzeiten zum Ausführen des Befehls entsprechen, erfüllt ist. A memory controller having a cache receives a command from a host, a set of criteria corresponding to the read and write response times to execute the command must be met; The memory control unit determines ranks of a first type and ranks of a second type which correspond to a plurality of data carriers which are connected to the memory control unit, the command being carried out taking into account the ranks of the first type. The paging speed corresponding to the ranks of the first type is adjusted to be less than a standard paging speed corresponding to the ranks of the second type, the set of criteria determining the read and write response times to perform the Correspond to the command is fulfilled.

Determining whether to use a repository to store data updated during a resynchronization

Provided are a method, system, and a computer program product for determining whether to use a repository to store data updated during a resynchronization. Writes to a primary storage are transferred to a secondary storage. A logical copy of the secondary storage as of a point-in-time is established. Writes to the secondary storage in the logical copy received from the primary storage during a logical copy duration after the point-in-time are stored in a repository that comprises less storage space than the secondary storage in the logical copy. The transferring of writes to the secondary storage is suspended. During the suspension writes to the primary storage are indicated in an out-of-synch data structure. A determination is made as to whether available storage space in the repository is sufficient to store writes transferred from the secondary storage while transferring the writes from the out-of-synch data structure in response to ending the suspension of the transferring of writes ...

Method, system, and program for managing meta data in a storage system and rebuilding lost meta data in cache

Disclosed is a method, system, and article of manufacture for processing modified meta data for data recovery operations. The meta data provides information on user data maintained in a storage device. The system determines whether meta data tracks maintained in a cache were modified and indicates in a non-volatile memory that the determined meta data tracks were modified. Data recovery operations may be initiated as a result of a system failure, such as a warmstart or coldstart recovery. During such data recovery operations, the system processes the non-volatile memory and the indications of modified meta data tracks therein to rebuild lost meta data tracks in the cache.

Steuergerät für peripheres Datenverarbeitungssystem

Encryption/decryption of data in storage systems

Provided are a method, system, and article of manufacture, wherein a controller receives encrypted data from a first storage unit coupled to the controller. The received encrypted data is stored in a second storage unit coupled to the controller, wherein the controller is capable of accessing the second storage unit faster in comparison to the first storage unit. The encrypted data is maintained in the second storage unit, until at least one condition is satisfied.

Maintaining information of a relationship of target volumes comprising logical copies of a source volume

Provided are a method, system, and article of manufacture for maintaining information of a relationship of target volumes comprising logical copies of a source volume. Information is maintained on a source volume having a plurality of data units and a plurality of target volumes created at different points-in-time maintaining a logical copy of the data units in the source volume for the different points-in-time. A source downstream pointer is generated for each data unit in the source volume to point to a corresponding data unit in a first target volume. For each target volume data unit whose data is maintained in the source volume or another one of the target volumes, a first upstream pointer is generated indicating one of the source and target volumes from which the target volume data unit inherits data. For each target volume data unit whose data is maintained in the source volume or another one of the target volumes, generating a second upstream pointer indicating one of the source and target volumes having the data for the data unit.

Method, system, and article of manufacture for preventing data loss

Provided are a method, system, and an article of manufacture for preventing data loss. Modified data is stored in a volatile storage. The stored modified data is copied onto a non-volatile storage. A determination is made as to whether the non-volatile storage should be checked for errors. In certain implementations, on determining that the nonvolatile storage should be checked for errors the non-volatile storage is checked for errors. If on checking the non-volatile storage is found to have an error, an indication of the error is provided.

MAINTAINING INFORMATION OF A RELATIONSHIP OF TARGET VOLUMES COMPRISING LOGICAL COPIES OF A SOURCE VOLUME

Provided are a method, system, and article of manufacture for maintaining information of a relationship of target volumes comprising logical copies of a source volume. Information is maintained on a source volume having a plurality of data units and a plurality of target volumes created at different points-in-time maintaining a logical copy of the data units in the source volume for the different points-in-time. A source downstream pointer is generated for each data unit in the source volume to point to a corresponding data unit in a first target volume. For each target volume data unit whose data is maintained in the source volume or another one of the target volumes, a first upstream pointer is generated indicating one of the source and target volumes from which the target volume data unit inherits data. For each target volume data unit whose data is maintained in the source volume or another one of the target volumes, generating a second upstream pointer indicating one of the source ...

Method and system for managing meta data

Disclosed is a method, system, and article of manufacture for managing meta data. The meta data provides information on data maintained in a storage device. The system receives a request for meta data from a process and determines whether the requested meta data is in cache. After determining that the requested meta data is not in cache, the system determines whether there are a sufficient number of allocatable segments in cache to stage in the meta data and allocates segments in cache to store the meta data after determining that there are enough allocatable segments in cache. The system stages the requested meta data into the allocated segments. Alternatively, after determining that the requested meta data is in cache, the system determines whether a second process has exclusive access to the meta data in cache. After determining that the second process does not have exclusive access, the system indicates to the first process that access to the meta data is permitted. Otherwise, after determining that the second process has exclusive access, the system notifies the first process that access to the meta data track will be provided at a later time when the second process relinquishes exclusive access.

Dynamisch eingestellter Schwellenwert zum Belegen eines sekundären Cache-Speichers

Das Belegen mit Daten, die in einen sekundären Cache-Speicher eines Datenspeichers eingegeben werden sollen, wird gesteuert durch Ermitteln einer Vergleichsmaßzahl potenzieller Daten, Einstellen eines Schwellenwerts der Vergleichsmaßzahl; Zurückweisen potenzieller Daten, die dem sekundären Cache-Speicher des Datenspeichers bereitgestellt werden, deren Vergleichsmaßzahl kleiner ist als der Schwellenwert; und Aufnehmen potenzieller Daten, deren Vergleichsmaßzahl gleich dem Schwellenwert oder größer als dieser ist. Die Einstellung des Schwellenwerts der Vergleichsmaßzahl wird ermittelt durch Vergleichen einer Referenzmaßzahl in Bezug auf Treffer von Daten, die in den sekundären Cache-Speicher des Datenspeichers zuletzt eingegeben wurden, mit einer Referenzmaßzahl in Bezug auf Treffer bei Daten, die aus dem sekundären Cache-Speicher des Datenspeichers verlagert wurden; Verringern des Schwellenwerts, wenn die Referenzmaßzahl der zuletzt eingegebenen Daten größer ist als die Referenzmaßzahl der ...

MANAGEMENT OF DESTAGE TASKS WITH LARGE NUMBER OF RANKS

A processor, operable in a computing storage environment, for each rank in a storage management device in the computing storage environment, allocates a lower maximum count defined by a predetermined lower maximum count of Task Control Blocks (TCBs) of a rank for performing destage operations, and a higher maximum count of TCBs to be implemented for performing a storage operation, and performs the storage operation using up to the lower maximum count of TCBs, yet only allows those TCBs above the lower maximum count to be allocated for performing the storage operation satisfying at least one criterion.

Managing write requests in cache directed to different storage groups

Provided are a method, system, and article of manufacture for managing write requests in cache directed to different storage groups. A determination is made of a high and low thresholds for a plurality of storage groups configured in a storage, wherein the high and low thresholds for one storage group indicate a high and low percentage of a cache that may be used to store write requests to the storage group. A determination is made of a number of tasks to assign to the storage groups based on the determined high and low thresholds for the storage groups, wherein each task assigned to one storage group destages write requests from the cache to the storage group.

Recovery from failure in data storage systems

Provided are a method, system, and article of manufacture, wherein a command is received at a first computational device coupled to a first adapter that is capable of allowing access to a data storage to the first computational device. The first computational device sends the command to a second computational device. The command is processed by a second adapter coupled to the second computational device, wherein the second adapter allows the second computational device to access the data storage, and wherein the second adapter accesses memory in the first computational device to process the command. In certain embodiments, the first adapter that allows the first computational device to access the data storage has failed.

Near continuous space-efficient data protection

A method for providing rolling continuous data protection of source data is disclosed. In one embodiment, such a method includes enabling a user to select source data and establish a first interval when point-in-time copies of the source data are generated. The method further enables the user to specify a first number of point-in-time copies to retain at the first interval. The method further enables the user to specify a second number of point-in-time copies to retain at a second interval, wherein the second interval is a (n>=2) multiple of the first interval. The method further enables the user to specify a third number of point-in-time copies to retain at a third interval, wherein the third interval is a (n>=2) multiple of the second interval. A corresponding apparatus and computer program product are also disclosed.

Method and system for selective space reclamation of data storage memory employing heat and relocation metrics

A method and computer program product for reclaiming space of a data storage memory of a data storage memory system, and a computer-implemented data storage memory system are provided. The method includes: determining heat metrics of data stored in the data storage memory; determining relocation metrics related to relocation of the data within the data storage memory; determining utility metrics of the data relating the heat metrics to the relocation metrics for the data; and making the data whose utility metric fails a utility metric threshold, available for space reclamation. Thus, data that otherwise may be evicted or demoted, but that meets or exceeds the utility metric threshold, is exempted from space reclamation and is instead maintained in the data storage memory.

Method and system for staging data into cache

Disclosed is a system for caching data. After determining a sequential access of a first memory area, such as a direct access storage device (DASD), a processing unit stages a group of data sets from the first memory area to a second memory, such as cache. The processing unit processes a data access request (DAR) for data sets in the first memory area that are included in the sequential access and reads the requested data sets from the second memory area. The processing unit determines trigger data set from a plurality of trigger data sets based on a trigger data set criteria. The processing unit then stages a next group of data sets from the first memory area to the second memory area in response to reading the determined trigger data set.

Data length control of access to a data bus

A method and system for controlling access to a bus for transferring data in the form of multibyte data streams. Data transfer agents are coupled to and request access to the bus to transfer data thereon. The system for controlling access to the bus comprises a bus arbiter responsive to the access requests of the data transfer agents, granting access to the bus to one data transfer agent at a time. A data length counter accumulates, during the grant of access, signals indicating the length of the data transferred between the bus and the data transfer agent. The data length counter indicates completion of the transfer of a predetermined length of data, and bus arbiter logic responds to the data length counter indicating the transfer completion, causing the bus arbiter to terminate the grant of access to the data transfer agent. The control of access to the bus is thus based on the precise measurement of the length of the transferred data, rather than on timers.

Apparatus, system, and method for identifying a faulty communication module

An apparatus, method, and system associates an identifier with a data packet. The identifier uniquely identifies a communication module, such as a host interface card, within a data storage system. In operation, a computer host sends a data packet to a server. The communication module receives the data packet and associates an identifier, unique to the communication module, with the data packet. The data packet is stored in a disk array, such as a Redundant Array of Independent Disks (RAID) system. When the computer host later requests the stored data packet, a validation module, which may be implemented within a PCI adapter such as a host interface card, retrieves the data packet and determines whether the data packet is corrupt. If the data packet is corrupt, the validation module identifies which host interface card corrupted the data with the use of the unique identifier associated with the data packet. The faulty communication module may then be removed from operation in the data storage ...

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.

System, apparatus, and process for evaluating projected cache sizes

A process, apparatus, and system for evaluating a projected cache size implement and manage one or more projected cache lists that each contains directory entries corresponding to a projected cache size. The projected cache size may be either smaller or larger than the actual size of a cache installed in a computer system. Using the projected cache list entries, performance statistics such as cache hit ratio and average access time are tracked for each list. The process, apparatus, and system may calculate performance parameters that describe the performance specific to the actual cache list and each projected cache list. The resulting performance statistics may be used to formulate an optimization parameter to be communicated to a user or an administrator application.

Adjustment of destage rate based on read and write response time requirements

A storage controller that includes a cache receives a command from a host, wherein a set of criteria corresponding to read and write response times for executing the command have to be satisfied. The storage controller determines ranks of a first type and ranks of a second type corresponding to a plurality of volumes coupled to the storage controller, wherein the command is to be executed with respect to the ranks of the first type. Destage rate corresponding to the ranks of the first type are adjusted to be less than a default destage rate corresponding to the ranks of the second type, wherein the set of criteria corresponding to the read and write response times for executing the command are satisfied.

ADAPTIVE CACHE PROMOTIONS IN A TWO LEVEL CACHING SYSTEM

Provided are a computer program product, system, and method for managing data in a first cache and a second cache. A reference count is maintained in the second cache for the page when the page is stored in the second cache. It is determined that the page is to be promoted from the second cache to the first cache. In response to determining that the reference count is greater than zero, the page is added to a Least Recently Used (LRU) end of an LRU list in the first cache. In response to determining that the reference count is less than or equal to zero, the page is added to a Most Recently Used (MRU) end of the LRU list in the first cache.

Intelligente Schreibcacheoperation für sequenzielle Datenspuren

In einer Datenverarbeitungsspeicherumgebung zum Auslagern von Daten von einem Permanentspeicher (NVS) zu einer Speichereinheit werden Schreibcacheoperationen für sequenzielle Datenspuren durch eine Prozessoreinheit bereitgestellt. Wenn festgestellt wird, dass eine erste Datenspur sequenziell ist, und wenn festgestellt wird, dass auch eine frühere Datenspur ebenfalls sequenziell ist, wird ein temporäres Bit, das der früheren Datenspur zugehörig ist, gelöscht, um das Auslagern von Daten der früheren Datenspur zu ermöglichen. Wenn festgestellt wird, dass ein temporäres Bit für eine aus einer Vielzahl von weiteren Datenspuren in einem Abschnitt aus einer Vielzahl von Abschnitten in einem geänderten Cachespeicher nicht gesetzt ist, wird für eine Auslagerungsoperation ein Abschnitt ausgewählt, der der einen aus der Vielzahl weiterer Datenspuren zugehörig ist. Wenn der NVS einen vorgegebenen Speicherschwellenwert überschreitet, wird ein vorgegebener Abschnitt aus der Vielzahl von Abschnitten für ...

MEMORY PRESERVED CACHE TO PREVENT DATA LOSS

A method, system, and computer program product for preserving data in a storage subsystem having dual cache and dual nonvolatile storage (NVS) through a failover from a failed cluster to a surviving cluster is provided. A memory preserved indicator is initiated to mark tracks on a cache of the surviving cluster to be preserved, the tracks having an image in an NVS of the failed cluster. A destage operation is performed to destage the marked tracks. Subsequent to a determination that each of the marked tracks have been destaged, the memory preserved indicator is disabled to remove the mark from the tracks. If the surviving cluster reboots previous to each of the marked tracks having been destaged, the cache is verified as a memory preserved cache, the marked tracks are retained for processing while all unmarked tracks are removed, and the marked tracks are processed.

VALIDATING STORED COPIES OF DATA IMAGES TO LOAD INTO MEMORY

Provided are a method, system, and article of manufacture for validating stored copies of data images to load into memory. An image of data is maintained in a memory, wherein the image in the memory includes a generation number. The image in the memory is written to at least two copies of the image to storage locations in response to a first event, wherein the generation number for the image in the memory is stored in the storage locations having the copies of the image. A check generation number is stored in a storage location. The image is loaded from at least one of the copies of the image in one of the storage locations to the memory in response to a second event The generation number for the image loaded into the memory. The check generation number is incremented in response to the second event. The generation numbers for the copies of the image in the storage locations and the check generation number are used to validate the copies of the image.

Verfahren, System, Computerprogramm-Produkt und Speichervorrichtung zur Steuerung einer Warteschlange von Anforderungen unterschiedlicher Priorität

Verfahren zur Steuerung von Warteschlangen auszuführender Anforderungen, worin jede Anforderung einer Ebene von einer Vielzahl an Prioritätsebenen zugeordnet ist, in dem die Schritte enthalten sind: Erzeugen einer Warteschlange einschließlich einer Vielzahl von Einträgen, worin jeder Eintrag einer Prioritätsebene entspricht und worin eine Vielzahl von Anforderungen bei einem Eintrag eingereiht werden kann; Empfangen einer neuen Anforderung mit einer zugeordneten Priorität zur Einreihung in die Warteschlange; Bestimmen eines Eintrags, auf den ein Zeiger verweist; Anpassen der Priorität, die der neuen Anforderung zugeordnet ist, mittels eines Wertes, wobei die angepasste Priorität einem anderen Eintrag als den, auf den der Zeiger verweist, zugeordnet wird; und Einreihen der neuen Anforderung bei einem Eintrag, welcher der angepassten Priorität zugeordnet ist.

Promotion of partial data segments in flash cache

Exemplary method, system, and computer program product embodiments for efficient track destage in secondary storage in a more effective manner, are provided. In one embodiment, by way of example only, for temporal bits employed with sequential bits for controlling the timing for destaging the track in a primary storage, the temporal bits and sequential bits are transferred from the primary storage to the secondary storage. The temporal bits are allowed to age on the secondary storage. Additional system and computer program product embodiments are disclosed and provide related advantages.

Apparatus, system, and method for mandatory end to end integrity checking in a storage system

An apparatus, system, and method are disclosed for mandatory end to end integrity checking. The apparatus includes a compatibility module configured to monitor data from a source and verify integrity information compatibility with a standard, and an integrity module configured to wrap the data from the source with additional integrity information. The system includes a source configured to send data over a network, a target configured to receive data over the network, the apparatus, a main memory module, a storage controller, and a storage device. The method includes monitoring data from a source, verifying integrity information compatibility with a standard, and wrapping the data from the source with additional integrity information.

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 for waking a predetermined number of the waiting I/O operations. A total number of I/O operations to be awoken at each of an iterated instance of the waking is limited. 16-. (canceled)7. A system for cache management in a computing storage environment , the method comprising: 'for a plurality of input/output (I/O) operations waiting to assemble complete data tracks from data segments, initiates a process, separate from a process responsible for the data assembly into the complete data tracks, for waking a predetermined number of the waiting I/O operations, wherein a total number of I/O operations to be awoken at each of an iterated instance of the waking is limited.', 'a processor device, operable in the computing storage environment, wherein the processor device8. The system of claim 7 , 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.9. The system of claim 8 , wherein the processor device removes claim 8 , pursuant to the waking process claim 8 , by a first I/O waiter claim 8 , the at least one complete data track off of a free list.10. The system of claim 9 , wherein the processor device wakes claim 9 , pursant to the waking process claim 9 , if additional complete data tracks are available on the free list claim 9 , at least a second I/O waiter to remove the additional complete data tracks off the free list.11. The system of claim 10 , wherein the processor device iterates through at least one additional waking process corresponding to a predetermined wake up depth.12. The system of claim 7 , wherein the processor device sets the predetermined number of waiting I/O operations to be awoken according to the waking process.13. The ...

Adaptive Cachespeicher-Umstufungen in einem Caching-System mit zwei Stufen

Es werden ein Computerprogrammprodukt, ein System und ein Verfahren zum Verwalten von Daten in einem ersten Cache-Speicher und in einem zweiten Cache-Speicher bereitgestellt. In dem zweiten Cache-Speicher wird eine Referenzanzahl für die Seite verwaltet, wenn die Seite in dem zweiten Cache-Speicher gespeichert ist. Es wird festgestellt, dass die Seite aus dem zweiten Cache-Speicher in den ersten Cache-Speicher umgestuft werden soll. Als Reaktion auf die Feststellung, dass die Referenzanzahl größer Null ist, wird die Seite an ein Least-Recently-Used-(LRU-)Ende einer LRU-Liste in dem ersten Cache-Speicher angefügt. Als Reaktion auf die Feststellung, dass die Referenzanzahl kleiner oder gleich Null ist, wird die Seite an ein Most-Recently-Used-(LRU-)Ende der LRU-Liste in dem ersten Cache-Speicher angefügt.

Data archiving using data compression of a flash copy

Embodiments of the disclosure relate to archiving data in a storage system. An exemplary embodiment comprises making a flash copy of data in a source volume, compressing data in the flash copy wherein each track of data is compressed into a set of data pages, and storing the compressed data pages in a target volume. Data extents for the target volume may be allocated from a pool of compressed data extents. After each stride worth of data is compressed and stored in the target volume, data may be destaged to avoid destage penalties. Data from the target volume may be decompressed from a flash copy of the target volume in a reverse process to restore each data track, when the archived data is needed. Data may be compressed and uncompressed using a Lempel-Ziv-Welch process.

MULTI-STAGE CACHE DIRECTORY AND VARIABLE CACHE-LINE SIZE FOR TIERED STORAGE ARCHITECTURES

A method in accordance with the invention includes providing first, second, and third storage tiers, wherein the first storage tier acts as a cache for the second storage tier, and the second storage tier acts as a cache for the third storage tier. The first storage tier uses a first cache line size corresponding to an extent size of the second storage tier. The second storage tier uses a second cache line size corresponding to an extent size of the third storage tier. The second cache line size is significantly larger than the first cache line size. The method further maintains, in the first storage tier, a first cache directory indicating which extents from the second storage tier are cached in the first storage tier, and a second cache directory indicating which extents from the third storage tier are cached in the second storage tier. 1. A method for improving the efficiency of a tiered storage architecture comprising at least three storage tiers , the method comprising:providing first, second, and third storage tiers, wherein the first storage tier acts as a cache for the second storage tier, and the second storage tier acts as a cache for the third storage tier;using, in the first storage tier, a first cache line size corresponding to an extent size of the second storage tier;using, in the second storage tier, a second cache line size corresponding to an extent size of the third storage tier, wherein the second cache line size is significantly larger than the first cache line size;maintaining, in the first storage tier, a first cache directory indicating which extents from the second storage tier are cached in the first storage tier; andmaintaining, in the first storage tier, a second cache directory indicating which extents from the third storage tier are cached in the second storage tier.2. The method of claim 1 , wherein the third storage tier has significantly more storage capacity than the second storage tier claim 1 , and the second storage tier has ...

Cascaded, point-in-time-copy architecture with data deduplication

A method for performing a write to a volume x in a cascaded architecture is described. In one embodiment, such a method includes determining whether the volume x has a child volume, wherein each of the volume x and the child volume have a target bit map (TBM) associated therewith. The method then determines whether the TBMs of both the volume x and the child volume are set. If the TBMs are set, the method finds a higher source (HS) volume from which to copy the desired data to the child volume. Finding the HS volume includes travelling up the cascaded architecture until the source of the data is found. Once the HS volume is found, the method copies the data from the HS volume to the child volume and performs the write to the volume x. A method for performing a read is also disclosed herein.

Recovery from cache and nvs out of sync

For cache/data management in a computing storage environment, incoming data segments into a Non Volatile Storage (NVS) device of the computing storage environment are validated against a bitmap to determine if the incoming data segments are currently in use. Those of the incoming data segments determined to be currently in use are designated to the computing storage environment to protect data integrity.

Deferred re-mru operations to reduce lock contention

Data operations, requiring a lock, are batched into a set of operations to be performed on a per-core basis. A global lock for the set of operations is periodically acquired, the set of operations is performed, and the global lock is freed so as to avoid excessive duty cycling of lock and unlock operations in the computing storage environment.

INTELLIGENT AND EFFICIENT RAID REBUILD TECHNIQUE

A method for servicing a redundant array of independent storage drives (i.e., RAID) includes performing a service call on the RAID by performing the following steps: (1) determining whether the RAID includes one or more consumed spare storage drives; (2) in the event the RAID includes one or more consumed spare storage drives, physically replacing the one or more consumed spare storage drive with one or more non-consumed spare storage drives; and (3) initiating a copy process that copies data from a storage drive that is predicted to fail to a non-consumed spare storage drive associated with the RAID. The service call may then be terminated. After the service call is terminated, the method waits for an indication that a number of non-consumed spare storage drives in the RAID has fallen below a selected threshold. A corresponding apparatus and computer program product are also disclosed. 1. A method for servicing a redundant array of independent storage drives (i.e. , RAID) , the RAID comprising a storage drive that is predicted to fail , the method comprising:performing a service call on the RAID, wherein performing the service call comprises: (1) determining whether the RAID comprises at least one consumed spare storage drive; (2) in the event the RAID comprises at least one consumed spare storage drive, physically replacing the at least one consumed spare storage drive with at least one non-consumed spare storage drive; and (3) initiating a copy process that copies data from the storage drive that is predicted to fail to a non-consumed spare storage drive;terminating the service call; andafter the service call has been terminated, waiting for an indication that a number of non-consumed spare storage drives in the RAID has fallen below a selected threshold.2. The method of claim 1 , further comprising claim 1 , after the data has been copied from the storage drive that is predicted to fail to the non-consumed spare storage drive claim 1 , logically replacing the ...

Nonsynchronous dasd control

Apparatus for controlling DASD in a manner that is not synchronous with channel operation, that is, transfer of commands and data are not limited to inter-record gap periods. A device interface processor controls which recording track is accessed by the DASD with data being transferred to and from a buffer. A device track indicator designates which recording tracks the device will move to in sequence. A channel interface processor controls the movement of data from and to the buffer and channel. A channel track indicator designates the recording track sequence in which the channel interface processor will access the data to be transferred. A method of operation is disclosed for utilizing the two indicators to enable the device and channel processors to communicate with each other in case the device reads incorrect records in a multi-track read operation.

Differential caching mechanism based on media I/O speed

A method for allocating space in a cache based on media I/O speed is disclosed herein. In certain embodiments, such a method may include storing, in a read cache, cache entries associated with faster-responding storage devices and cache entries associated with slower-responding storage devices. The method may further include implementing an eviction policy in the read cache. This eviction policy may include demoting, from the read cache, the cache entries of faster-responding storage devices faster than the cache entries of slower-responding storage devices, all other variables being equal. In certain embodiments, the eviction policy may further include demoting, from the read cache, cache entries having a lower read-hit ratio faster than cache entries having a higher read-hit ratio, all other variables being equal. A corresponding computer program product and apparatus are also disclosed and claimed herein.

Encryption/decryption of data in storage systems

Provided are a method, system, and article of manufacture, wherein a controller receives encrypted data from a first storage unit coupled to the controller. The received encrypted data is stored in a second storage unit coupled to the controller, wherein the controller is capable of accessing the second storage unit faster in comparison to the first storage unit. The encrypted data is maintained in the second storage unit, until at least one condition is satisfied.

Adaptive cache promotions in a two-tier caching system

Verfahren zum Verwalten von Daten in einem ersten Cache-Speicher (14) und in einem zweiten Cache-Speicher (18), aufweisend:Verwalten, unter Verwendung eines Prozessors eines Computers, einer Referenzanzahl für eine Seite in dem zweiten Cache-Speicher (18), wenn die Seite in dem zweiten Cache-Speicher (18) gespeichert ist;Feststellen, dass die Seite aus dem zweiten Cache-Speicher (18) in den ersten Cache-Speicher (14) umgestuft werden soll;als Reaktion auf die Feststellung, dass die Referenzanzahl größer Null ist, Anfügen der Seite an ein Least-Recently-Used-(LRU-)Ende einer LRU-Liste (54) in dem ersten Cache-Speicher (14); undals Reaktion auf die Feststellung, dass die Referenzanzahl kleiner oder gleich Null ist, Anfügen der Seite an ein Most-Recently-Used-(MRU-)Ende der LRU-Liste (54) in dem ersten Cache-Speicher (14). A method for managing data in a first cache (14) and in a second cache (18), comprising: maintaining, using a processor of a computer, a reference count for a page in the second cache (18) if the page is stored in the second cache (18); determining that the page should be promoted from the second cache (18) to the first cache (14); in response to determining that the reference count is greater than zero, appending the page to a Least Recently Used (LRU) end of an LRU list (54) in the first cache memory (14); andin response to determining that the reference count is less than or equal to zero, appending the page to a Most Recently Used (MRU) end of the LRU list (54) in the first cache (14).

Recovery from cache and NVS out of sync

For cache/data management in a computing storage environment, incoming data segments into a Non Volatile Storage (NVS) device of the computing storage environment are validated against a bitmap to determine if the incoming data segments are currently in use. Those of the incoming data segments determined to be currently in use are designated to the computing storage environment to protect data integrity.

A storage subsystem with hashed cache addressing

Determining whether to use a full volume or repository for a logical copy backup space

Provided are a method, system, and article of manufacture for determining whether to use a full volume or repository for a logical copy backup space. A determination is made of a source volume to backup using a logical copy operation. The logical copy operation is completed upon indicating the source volume data to backup. During a logical copy duration, point-in-time data in the source volume as of a point-in-time when the logical copy was established is copied to a backup space in response to receiving an update to the point-in-time data. A history of writes to the source volume is processed to determine whether to allocate a full target volume as the backup space providing a corresponding data unit for each data unit in the source volume or allocate a repository as the backup space, wherein the repository uses less storage space than the full target volume. The logical copy operation using the determined full target volume or repository as the backup space is initiated.

Decryption of data in storage systems

System for concurrent cache data access by maintaining and selectively merging multiple ranked part copies

A system for providing multiple hosts with concurrent access to cached data by selectively generating, maintaining, modifying, and consolidating multiple versions of data items in cache memory to efficiently accommodate data access requests by the hosts. Data associated with a logical track is represented in cache by a number of cache track image parts. Each part represents one or more records in cache, where multiple parts may exist in cache for the same logical track. The provision of multiple parts supports concurrent access by multiple operations or "processes" to data associated with a track. Namely, each part is given a "status" selected from a predetermined catalog of statuses; the assigned status thus establishes the permissible manner of accessing that part. Depending upon a part's status, the part may be used by one process (e.g. Read) or by multiple processes concurrently (e.g. Read and Destage). Other part statuses dedicate a part to a single process (e.g. Write). Multiple parts, not being actively used by a process, may be combined by a merge function to represent the most current image of the track.

Apparatus, system, and method for flushing cache data

An apparatus, system, and method are disclosed for flushing cache data in a cache system. The apparatus includes a zero module and a flush module. The zero module executes an internal processor instruction to zero out a zero memory segment of a nonvolatile memory and a processor cache in response to a loss of primary power to the processor cache. The flush module flushes modified data from an address in the processor cache to a flush memory segment of the nonvolatile memory before the zero module puts a zero in the address. Advantageously, the zero memory segment is reserved within the memory and used to zero out the processor cache, effectively flushing the existing data from the processor cache to a flush memory segment of the memory.

Manage cache memory paging check times

System (100) zum Verwalten von Cachespeicher-Auslagerungsüberprüfungszeiten, das aufweist:einen Cachespeicher (120) undeinen Prozessor (130), der mit dem Cachespeicher verbunden (140) ist, wobei der Prozessor konfiguriert ist zum:Verwenden eines ersten Thread (200) zum fortlaufenden Ermitteln einer gewünschten Überprüfungszeit für ein Überprüfen der Mehrzahl von Speicherspuren in dem Cachespeicher undVerwenden eines zweiten Thread (300), zum fortlaufenden Steuern einer tatsächlichen Überprüfungszeit der Mehrzahl von Speicherspuren in dem Cachespeicher auf Grundlage der fortlaufend ermittelten gewünschten Überprüfungszeit,wobei der Prozessor (130) beim fortlaufenden Ermitteln (200) der gewünschten Überprüfungszeit konfiguriert ist zum:Überwachen (205) des Cachespeichers (120) auf Auslagerungskonflikte (210) auf eine im Wesentlichen fortlaufende Weise undVerlängern (215) der gewünschten Überprüfungszeit um eine vorgegebene Zeitspanne, wenn der Cachespeicher von Auslagerungskonflikten betroffen ist;Überwachen (205) des Cachespeichers auf Schwingungen (220) auf eine im Wesentlichen fortlaufende Weise undVerkürzen (225) der gewünschten Überprüfungszeit um einen vorgegebenen Prozentanteil, wenn der Cachespeicher von Schwingungen betroffen ist. A system (100) for managing cache memory destage check times, comprising: a cache memory (120); and a processor (130) coupled (140) to the cache memory, the processor being configured to: use a first thread (200) to continuously determining a desired scan time for scanning the plurality of storage tracks in the cache and using a second thread (300) to continuously control an actual scan time of the plurality of storage tracks in the cache based on the continuously determined desired scan time, wherein the processor (130) while continuously determining (200) the desired scan time, is configured to: monitor (205) the cache (120) for destage conflicts (210) in a substantially continuous manner; and extend (215) the desired scan time by ...

Data transfer in a data processing system

The peripheral cache DASD subsystem (19) is connected to one or more host processors (10). A channel connection (12) between the host processor and the peripheral subsystem has a much higher burst rate then the burst data transfer rate of a DASD (20) while having an extended signal propagation time preventing rapid exchanges of interactive control signals. The branch write occurs in that data is written both to the DASD and to the cache (16) simultaneously. The write domain is established in the subsystem by the host processor in a number of records to be updated or number of records to be formatted on the DASD when the available cache space is compared with a needed cache space for the entire write domain. Whenever the available cache space is less than the write domain needs, then the data transfer is subsetted to match the available cache space. Calculations for determining the maximum cache space is described and sets of machine operations are disclosed for effecting the above operations.

Support for partial data segments in flash caches

Verfahren zum Unterstützen von unvollständigen Datensegmenten in einer Datenverarbeitungsspeicherumgebung mit langsameren und schnelleren Geschwindigkeitsebenen des Cache-Speichers durch einen Prozessor, wobei das Verfahren aufweist:- Einrichten eines Mechanismus zum Verlagern von Daten, der so ausgelegt ist, dass er ausführt:◯ Zulassen, dass die unvollständigen Datensegmente in der schnelleren Cache-Speicher-Ebene für eine längere Zeitdauer bleiben als wenigstens ein vollständiges Datensegment und◯ Umsetzen einer Bevorzugung der Verlagerung der unvollständigen Datensegmente zu der langsameren Cache-Speicher-Ebene auf der Grundlage einer Anzahl von Leerstellen und/oder einer Daten-Vergleichsmaßzahl, die die Häufigkeit angibt, mit der die Daten verwendet werden, wobei:■ ein erstes der unvollständigen Datensegmente, das eine kleinere Anzahl von Leerstellen und/oder eine aktuellere Daten-Vergleichsmaßzahl aufweist, vor einem zweiten der unvollständigen Datensegmente, das eine größere Anzahl von Leerstellen und/oder eine weniger aktuelle Daten-Vergleichsmaßzahl aufweist, zu der langsameren Cache-Speicher-Ebene verlagert wird; und■ das erste der unvollständigen Datensegmente verworfen wird, wenn das erste der unvollständigen Datensegmente eine aktuellere Daten-Vergleichsmaßzahl und mehr als eine im Voraus festgelegte Anzahl von Leerstellen aufweist. A method for supporting incomplete data segments in a computing memory environment with slower and faster cache memory speed tiers by a processor, the method comprising:- establishing a mechanism for moving data that is adapted to perform:◯ allowing the incomplete data segments remain in the faster cache memory tier for a longer period of time than at least one complete data segment and◯ implement a preference of moving the incomplete data segments to the slower cache memory tier based on a number of vacancies and/or a data -comparison measure indicating the frequency with which the data is used, where:■ a first of the ...

Using different algorithms to destage different types of data from cache

Provided are a method, system, and article of manufacture for using different algorithms to destage different types of data from cache. A first destaging algorithm is used to destage a first type of data to a storage for a first duration. A second destaging algorithm is used to destage a second type of data to the storage for a second duration.

Determining whether to use a repository to store data updated during a resynchronization

Provided are a method, system, and a computer program product for determining whether to use a repository to store data updated during a resynchronization. Writes to a primary storage are transferred to a secondary storage. A logical copy of the secondary storage as of a point-in-time is established. Writes to the secondary storage in the logical copy received from the primary storage during a logical copy duration after the point-in-time are stored in a repository that comprises less storage space than the secondary storage in the logical copy. The transferring of writes to the secondary storage is suspended. During the suspension writes to the primary storage are indicated in an out-of-synch data structure. A determination is made as to whether available storage space in the repository is sufficient to store writes transferred from the secondary storage while transferring the writes from the out-of-synch data structure in response to ending the suspension of the transferring of writes from the primary to the secondary storages. The repository is used to store data in the secondary storage as of the point-in-time that is to be updated by writes transferred from the primary storage following the ending of the suspension in response to determining that the available storage space in the repository is sufficient to store writes transferred from the secondary storage while transferring the writes indicated in the out-of-synch data structure.

Flushing stale data from a PCI bus system read prefetch buffer

A system and method for flushing stale data from a read prefetch buffer of a PCI bus system which transfers data in the form of data streams of contiguous blocks. The PCI bus system comprises a channel adapter at one PCI bus that issues read commands, a data source coupled to a second PCI bus, and a prefetch buffer that prefetches the blocks of read data. A prefetch counter posts the remaining number blocks to be read and transferred, posting the prefetch count at a storage location of a storage memory mapped to a prefetch location in the prefetch buffer. The prefetch count is written to the storage location by a prefetch count write command. The system for flushing stale data from the prefetch buffer comprises a key detector for sensing an unique identifier of the prefetch count write command. Data path logic responds to the key detector, determining the prefetch location of the prefetch buffer from the mapped storage location of the prefetch count write command, and flushing any prefetch data at the determined prefetch location.

Method of determining whether to use a full volume or repository for a logical copy backup space and apparatus therefor

Provided are a method, system, and computer program product for determining whether to use a full volume or repository for a logical copy backup space. A determination is made of a source volume to backup using a logical copy operation. The logical copy operation is completed upon indicating the source volume data to backup. During a logical copy duration, point-in-time data in the source volume as of a point-in-time when the logical copy was established is copied to a backup space in response to receiving an update to the point- in-time data. A history of writes to the source volume is processed to determine whether to allocate a full target volume as the backup space providing a corresponding data unit for each data unit in the source volume or allocate a repository as the backup space, wherein the repository uses less storage space than the full target volume. The logical copy operation using the determined full target volume or repository as the backup space is initiated.

Apparatus, system, and method for storing and retrieving compressed data

An apparatus, system, and method are disclosed for storing and retrieving compressed data. A compression module compresses a data file organized in logical tracks. A ratio module determines a track compression ratio. The track compression ratio is a ratio of an integer value n to one. A destage module destages a single directory entry for the data file to a directory. The directory entry points to a zeroth track on a hard disk drive. The destage module further destages the data file sequentially to tracks of the hard disk drive from the zeroth track with n logical tracks of the data file stored on one physical track of the hard disk drive. A stage module stages a kth logical track from a physical track of the hard disk drive. The physical track is specified by an integer value of k divided by n.

Cyclic point-in-time-copy architecture with data deduplication

A method for performing a write to a volume x in a cyclic point-in-time-copy architecture is described. In one embodiment, such a method includes determining whether the volume x has a child volume. The method then determines whether the target bit maps (TBMs) of both the volume x and the child volume are set. If the TBMs are set, the method finds a higher source (HS) volume from which to copy the desired data to the child volume. Once the HS volume is found, the method determines whether the HS volume and the child volume are the same volume. If the HS volume and the child volume are not the same volume, the method copies the data from the HS volume to the child volume. The method then performs the write to the volume x.

Fuzzy counters for nvs to reduce lock contention

A system for data management in a computing storage environment includes a processor device, operable in the computing storage environment, that divides a plurality of counters tracking write and discard storage operations through Non Volatile Storage (NVS) space into first, accurate, and second, fuzzy, groups where the first, accurate, group is one of incremented and decremented per each write and discard storage operation, while the second, fuzzy, group is one of incremented and decremented on a more infrequent basis as compared to the first, accurate group.

Caching data in a storage system having multiple caches

Provided are a computer program product, system, and method for using an attribute of a write request to determine where to cache data in a storage system having multiple caches including non-volatile storage cache in a sequential access storage device. Received modified tracks are cached in the non- volatile storage device integrated with the sequential access storage device in response to determining to cache the modified tracks. A write request having modified tracks is received. A determination is made as to whether an attribute of the received write request satisfies a condition. The received modified tracks for the write request are cached in the non- volatile storage device in response to determining that the determined attribute does not satisfy the condition. A destage request is added to a request queue for the received write request having the determined attribute not satisfying the condition.

Selecting a path comprising ports on primary and secondary clusters to use to transmit data at a primary volume to a secondary volume

Provided are a method, system and program for selecting a path comprising ports on primary and secondary clusters to use to transmit data at a primary volume to a secondary volume. A request is received to copy data from a primary storage location to a secondary storage location. A determination is made from a plurality of primary clusters of an owner primary cluster for the primary storage location, wherein the primary clusters are configured to access the primary storage location. A determination is made as to whether there is at least one port on the owner primary cluster providing an available path to the secondary storage location. One port on the owner primary cluster is selected to use to copy the data to the secondary storage location in response to determining that there is at least one port on the owner primary cluster available to transmit to the secondary storage location.

Intelligente Schreibcacheoperationen für sequenzielle Datenspuren

Verfahren für Schreibcacheoperationen für sequenzielle Datenspuren durch eine Prozessoreinheit (40, 41, 42, 68a, 78a) in einer Datenverarbeitungsspeicherumgebung zum Auslagern von Daten von einem Permanentspeicher, NVS (46, 69a, 79a), zu einer Speichereinheit (30, 65a, 75a), wobei das Verfahren aufweist:wenn festgestellt wird, dass eine erste Datenspur sequenziell ist, und wenn ferner festgestellt wird, dass eine frühere Datenspur ebenfalls sequenziell ist, Löschen (112) eines temporären Bits, das der früheren Datenspur zugehörig ist, um das Auslagern von Daten der früheren Datenspur zu ermöglichen; undwenn festgestellt wird, dass ein temporäres Bit für eine aus einer Vielzahl weiterer Datenspuren in einem aus einer Vielzahl von Abschnitten in einem geänderten Cachespeicher nicht gesetzt ist, Auswählen (136) eines Abschnitts, der der einen aus der Vielzahl weiterer Datenspuren zugehörig ist, für eine Auslagerungsoperation, wobei ein vorgegebener Abschnitt aus der Vielzahl von Abschnitten für die Auslagerungsoperation ausgewählt (142) wird, wenn der NVS (46, 69a, 79a) einen vorgegebenen Speicherschwellenwert überschreitet.

Determining whether to use a repository to store data updated during a resynchronization

Provided are a method, system, and a computer program product for determining whether to use a repository to store data updated during a resynchronization. Writes to a primary storage are transferred to a secondary storage. A logical copy of the secondary storage as of a point-in-time is established. Writes to the secondary storage in the logical copy received from the primary storage during a logical copy duration after the point-in-time are stored in a repository that comprises less storage space than the secondary storage in the logical copy. The transferring of writes to the secondary storage is suspended. During the suspension writes to the primary storage are indicated in an out-of-synch data structure. A determination is made as to whether available storage space in the repository is sufficient to store writes transferred from the secondary storage while transferring the writes from the out-of-synch data structure in response to ending the suspension of the transferring of writes from the primary to the secondary storages. The repository is used to store data in the secondary storage as of the point-in-time that is to be updated by writes transferred from the primary storage following the ending of the suspension in response to determining that the available storage space in the repository is sufficient to store writes transferred from the secondary storage while transferring the writes indicated in the out-of-synch data structure.

Determining whether to use a repository to store data updated during a resynchronization

Determining whether to use a repository to store data updated during a resynchronization

Periodic destages from inside and outside diameters of disks to improve read response times

A storage controlled 102) that includes a cache(108), receives a command from a host( 104a, 104b,...104n), wherein a set of criteria corresponding to read response times for executing the command have to be satisfied(402). A destage application that destages tracks based at least on recency of usage and spatial location of the tracks is executed, wherein a spatial ordering of the tracks is maintained in a data structure, and the destage application traverses the spatial ordering of the tracks(404). Tracks are destaged from at least inside or outside diameters of disks at periodic intervals, while traversing the spatial ordering of the tracks, wherein the set of criteria corresponding to the read response times for executing the command are satisfied(406).

Error checking and recovery of transmitted data

An apparatus, system, and method are disclosed for data error checking and recovery in a data storage device. A redundancy check module creates a redundancy check for data on a data storage device in a SCSI End-to-End Checking Standard environment and a redundancy check storage module stores the redundancy check in a guard associated with the data.

Determining whether to cache storage system writes in a non-volatile cache

Integrating a flash cache into large storage systems

An I/O enclosure module is provided with one or more I/O enclosures having a plurality of slots for receiving electronic devices. A host adapter is connected a first slot of the I/O enclosure module and is configured to connect a host to the I/O enclosure. A device adapter is connected to a second slot of the I/O enclosure module and is configured to connect a storage device to the I/O enclosure module. A flash cache is connected to a third slot of the I/O enclosure module and includes a flash-based memory configured to cache data associated with data requests handled through the I/O enclosure module. A primary processor complex manages data requests handled through the I/O enclosure module by communicating with the host adapter, device adapter, and flash cache to manage to the data requests.

Method, system, and article of manufacture for the detection of misdirected data

Provided are a method, system and article of manufacture, wherein in certain embodiments an I/O command from a host is received at a first storage unit. An identifier is generated that identifies a destination to which the I/O command is to be transmitted from the first storage unit. The I/O command is augmented with the generated identifier at the first storage unit. The augmented I/O command is transmitted. In certain other embodiments, an I/O command is received at a storage unit, wherein the storage unit is associated with a storage unit identifier. A determination is made at the storage unit, whether the I/O command is associated with an identifier that identifies a destination for which the I/O command is intended. A further determination is made, at the storage unit, whether the identifier is the same as the storage unit identifier, in response to determining that the identifier associated with the I/O command identifies the destination for which the I/O command is intended.

Integrating a flash cache into large storage systems

Method, system, and article of manufacture for the detection of misdirected data

Method, system, and article of manufacture for the detection of misdirected data

Provided are a method, system and article of manufacture, wherein in certain embodiments an I/O command from a host is received at a first storage unit. An identifier is generated that identifies a destination to which the I/O command is to be transmitted from the first storage unit. The I/O command is augmented with the generated identifier at the first storage unit. The augmented I/O command is transmitted. In certain other embodiments, an I/O command is received at a storage unit, wherein the storage unit is associated with a storage unit identifier. A determination is made at the storage unit, whether the I/O command is associated with an identifier that identifies a destination for which the I/O command is intended. A further determination is made, at the storage unit, whether the identifier is the same as the storage unit identifier, in response to determining that the identifier associated with the I/O command identifies the destination for which the I/O command is intended.

Validating stored copies of data images to load into memory

Provided are a method, system, and article of manufacture for validating stored copies of data images to load into memory. An image of data is maintained in a memory, wherein the image in the memory includes a generation number. The image in the memory is written to at least two copies of the image to storage locations in response to a first event, wherein the generation number for the image in the memory is stored in the storage locations having the copies of the image. A check generation number is stored in a storage location. The image is loaded from at least one of the copies of the image in one of the storage locations to the memory in response to a second event The generation number for the image loaded into the memory. The check generation number is incremented in response to the second event. The generation numbers for the copies of the image in the storage locations and the check generation number are used to validate the copies of the image.

Validating stored copies of data images to load into memory

Provided are a method, system, and article of manufacture for validating stored copies of data images to load into memory. An image of data is maintained in a memory, wherein the image in the memory includes a generation number. The image in the memory is written to at least two copies of the image to storage locations in response to a first event, wherein the generation number for the image in the memory is stored in the storage locations having the copies of the image. A check generation number is stored in a storage location. The image is loaded from at least one of the copies of the image in one of the storage locations to the memory in response to a second event. The generation number for the image loaded into the memory. The check generation number is incremented in response to the second event. The generation numbers for the copies of the image in the storage locations and the check generation number are used to validate the copies of the image.

Promotion of partial data segments in flash cache

Exemplary method, system, and computer program product embodiments for efficient track destage in secondary storage in a more effective manner, are provided. In one embodiment, by way of example only, for temporal bits employed with sequential bits for controlling the timing for destaging the track in a primary storage, the temporal bits and sequential bits are transferred from the primary storage to the secondary storage. The temporal bits are allowed to age on the secondary storage. Additional system and computer program product embodiments are disclosed and provide related advantages.

Recovery from failure in data storage systems

Deleting relations in multi-target, point-in-time-copy architectures with data deduplication

A method for deleting a relation between a source and a target in a multi-target architecture is described. The multi-target architecture includes a source and multiple targets mapped thereto. In one embodiment, such a method includes initially identifying a relation for deletion from the multi-target architecture. A target associated with the relation is then identified. The method then identifies a sibling target that inherits data from the target. Once the target and the sibling target are identified, the method copies the data from the target to the sibling target. The relation between the source and the target is then deleted. A corresponding computer program product is also disclosed and claimed herein.

Deferred re-MRU operations to reduce lock contention

Data operations, requiring a lock, are batched into a set of operations to be performed on a per-core basis. A global lock for the set of operations is periodically acquired, the set of operations is performed, and the global lock is freed so as to avoid excessive duty cycling of lock and unlock operations in the computing storage environment.

Management of destage tasks with large number of ranks

A processor, operable in a computing storage environment, for each rank in a storage management device in the computing storage environment, allocates a lower maximum count defined by a predetermined lower maximum count of Task Control Blocks (TCBs) of a rank for performing destage operations, and a higher maximum count of TCBs to be implemented for performing a storage operation, and performs the storage operation using up to the lower maximum count of TCBs, yet only allows those TCBs above the lower maximum count to be allocated for performing the storage operation satisfying at least one criterion.