Abstract: A storage system and a method for copying data is provided. The method includes storing data at a first storage unit of a primary site, transferring the data from the first storage unit to a second storage unit of a remote site and updating shadow storage unit metadata to reflect the storing of the data at the first storage unit, and copying, in response to the updating of the shadow storage unit metadata, the data from an entity that differs from the shadow storage unit to a third storage unit.

Abstract: A method of enabling state save and debug operations for co-routines for first failure data capture (FFDC) in an event-driven environment. A stack management utility allocates space for a context structure, which includes a state field, and a stack pointer in a buffer. A context management utility initializes a first context structure of a first co-routine and saves a state of the first context structure in response to an execution request for a second co-routine. The context management utility sets a second context structure as a current context. When execution of the current context is complete, the context management utility restores the first context structure of the first co-routine as the current context. If the state field is not set to a valid value, a state save function “state saves” all allocated co-routine stacks and context structures, restores the entire system to a previous valid state, and restarts operations.

Abstract: Generating a consistent point in time copy of data in a source volume and a target volume is achieved responsively to a first data modification request by writing a first altered version of the data onto a single source volume, asynchronously transferring the first altered version from the first storage site to a target volume located at a remote second storage site, while avoiding copying the first altered version onto other volumes at the first storage site. While asynchronously transferring the first altered version de-queuing a second modification request, and responsively to the second modification request synchronously transferring the first altered version from the first storage site to the target volume. Then a second altered version of the data is written to the single source volume and a copy transferred to the target volume in like manner.

Abstract: Systems and methods for input/output command management. In some cases of a write command received from a host, a maximum capacity limit relating to primary memory may be disregarded because data relating to the write command is written to backup memory prior to acknowledging the write command. In some of these cases, timeout is less likely than if the maximum capacity limit had been respected.

Abstract: A storage system, including: (a) a primary storage entity utilized for storing a data-set of the storage system; (b) a secondary storage entity utilized for backing-up the data within the primary storage entity; (c) a flushing management module adapted to identify within the primary storage entity two groups of dirty data blocks, each group is comprised of dirty data blocks which are arranged within the secondary storage entity in a successive sequence, and to further identify within the primary storage entity a further group of backed-up data blocks which are arranged within the secondary storage entity in a successive sequence intermediately in-between the two identified groups of dirty data blocks; and (d) said flushing management module is adapted to combine the group of backed-up data blocks together with the two identified groups of dirty data blocks to form a successive extended flush sequence and to destage it to the secondary storage entity.

Abstract: Provided are a method, system, and article of manufacture for a replication engine communicating with a splitter to split writes between a storage controller and replication engine. Communication is initiated with the splitter implemented in a storage controller managing access to primary volumes. A command is sent to the splitter to copy writes to one primary volume to the replication engine. Write data is received from the splitter to one of the primary volumes following the splitter receiving the command to copy the writes to the replication engine. A determination is made of a copy services function to use for the received data. The determined copy services function is invoked to transfer the received data to a secondary storage volume.

Abstract: Techniques are provided for performing a copy operation. A fast reverse restore command indicating a new source and a new target is received, wherein the new source is an original target and the new target is an original source. A synchronous scan is performed on the new target. A new target structure associated with the new target is updated using a new source structure associated with the new source. Techniques are also provided for performing a copy operation in which a fast reverse restore command is received after an instant virtual copy has been performed from a new target to a new source and wherein the fast reverse restore command is performed before a background copy has been performed by the instant virtual copy.

Abstract: A method for synchronizing data storage systems is provided. The method comprises designating a relationship between a first data storage system and a second data storage system, such that data stored in the first data storage system is copied to the second data storage system, in response to determining that the data stored in the first data storage system has been modified; receiving a first request to modify data stored in a first data block of a first storage volume in the first data storage system, wherein the data block is modified according to the first request; determining that the first data block has not been successfully synchronized when the modified data stored in the first data block is not copied to the second data storage system; and executing a process to retry synchronization of the first data block until synchronization of the first data block is successful, without suspending the relationship while the process is executed.

Abstract: 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.

Abstract: A method for checking an alternative system test, the method includes: determining a relationship between (i) utilization of resources during an execution of a group of programs by a first system when operating in a non-testing mode and (ii) utilization of resources during an executive of an alternative system test by the alternative system; wherein the alternative system test comprises at least on program of the group of programs.

Abstract: 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.

Abstract: A computer-implemented method for efficient data storage is provided. A first storage medium associates data stored on one or more data storage media with a unique identification value (ID) for the purpose of determining de-duplication status of the data. In response to receiving a request to read the data from a logical address, the first storage medium retrieves the data from a second storage medium based on the unique ID. In response to receiving a request to write the data to a logical address, the one or more data storage media store at least one copy of the data based on the de-duplication status of the data.

Abstract: A method for re-establishing a backup relationship between first and second volumes associated with one or more storage media in a data storage system is provided. The method comprises storing first information for preserving the backup relationship, in response to or in advance of receiving a request to terminate the backup relationship; recording changes to the first or second volumes that occur subsequent to terminating the backup relationship; and re-establishing the backup relationship between the first and second volumes according to the first information such that the first and second volumes are synchronized by merging the recorded changes with the first or second volumes.

Abstract: A method to maintain write operation atomicity where a write operation crosses a data storage medium track boundary. The method supplies a storage controller comprising a host adapter, a processor, and a NVS. The primary host adapter receives from a host computer a write request and data. The method determines if the write request will cross a data storage medium track boundary. If the write request will cross a data storage medium track boundary, the method indicates to the host adapter that the write request comprises a two-track transfer, and writes the data to the primary NVS as the data is received. If the host computer fails prior to providing all the data to the storage controller, the method discards the data written to the NVS to ensure write operation atomicity.

Abstract: Techniques are provided for performing a copy operation. A fast reverse restore command indicating a new source and a new target is received, wherein the new source is an original target and the new target is an original source. A synchronous scan is performed on the new target. A new target structure associated with the new target is updated using a new source structure associated with the new source. Techniques are also provided for performing a copy operation in which a fast reverse restore command is received after an instant virtual copy has been performed from a new target to a new source and wherein the fast reverse restore command is performed before a background copy has been performed by the instant virtual copy.

Abstract: An apparatus, system, and method are disclosed for performing an incremental resynchronization between two unrelated volumes when a third volume fails. The apparatus, system, and method include initiating registration of changed tracks; keeping track of bytes in flight activities between a local volume and an intermediate volume; recording the changed tracks in bitmaps at the local volume; stopping the recording of the changed tracks; and starting a resynchronization process by sending the changed tracks to a recovery volume.

Abstract: A novel and useful mechanism and method for writing data updates to a data cache subsystem of a storage controller. Updates received by the storage controller requiring storage allocation on a repository volume are delayed prior to being written to the data cache subsystem. The delay is based on the storage utilization of the repository volume. As the utilization of the repository volume increases, the cache write delay increases, thereby limiting the possibility that there will still be any updates in the data cache subsystem waiting to be destaged to the repository volume when the repository volume is fully utilized. When the repository volume is fully utilized all writes to the data cache of updates that will cause destage of tracks in the repository volume are stopped, thereby causing an infinite delay.

Abstract: Automatic Selection of Storage Volumes in a Data Storage System A method of selecting a target volume in a storage system is provided. The method comprises defining one or more parameters for a plurality of storage volumes in the storage system according to user preference; dynamically collecting information related to the parameters while the storage volumes are used; receiving a request to backup a first source volume in the storage system; and selecting or creating the target volume based on the collected information.

Abstract: A method for consistent version of multiple information items is provided. The method includes receiving a conditional request to copy a version of multiple information items at a condition fulfillment point of time that is associated with a fulfillment of a condition of the conditional request. Then determining that the condition is fulfilled, and participating in generating a condition fulfillment point in time version of the multiple information items.

Abstract: A method for improving performance in a storage system is provided. The method comprises receiving a request to destage a partial stride of data from a storage cache; reserving space for a full stride of data on one or more storage devices; allocating the partial stride of data to the reserved space; adding padding for unallocated blocks, wherein the unallocated blocks are reserved for future updates; and destaging the full stride of data to the storage devices, wherein the full stride of data comprises the allocated partial stride of data and the padded unallocated blocks.