Abstract: Embodiments of the present disclosure relate to a new approach for workload balancing in a system. A computer-implemented method comprises obtaining a configuration of a system, wherein the configuration includes a connection relationship between components in the system. The method further comprises determining a workload threshold of a given component in the components based on the configuration, wherein a workload threshold of an upstream component of the given component is associated with a workload limit of the upstream component and a workload limit of the given component. The method further comprises determining a utilization rate of the given component based at least partially on a workload amount of the given component, the workload threshold of the given component, and the workload threshold of the upstream component.

Abstract: Withdrawal of a point-in-time snap copy relationship or a portion of such a relationship, is managed in a manner which can obviate disruption of consistency groups due to the withdrawal. If the withdrawal request is directed to a subrange of the original snap copy relationship, the snap copy relationship is split by creating one or more point-in-time snap copy relationships over one or more subranges of tracks of the snap copy source. A determination is made as to whether to delay execution of the withdrawal request to temporarily preserve data of the withdrawal range. Disruptions to completion of consistency groups may be avoided by selectively delaying the withdrawal of a snap copy relationship corresponding to the withdrawal subrange. In so far as the host is involved, a host may treat the withdrawal request as immediately granted without delay. Other aspects may be realized, depending upon the particular application.

Abstract: Provided are techniques for performing a recovery copy command to restore a safeguarded copy backup to a production volume. In response to receiving a recovery copy command, a production target data structure is created. A read operation is received for data for a storage location. In response to determining that the data for the storage location is in a cache of a host and a generation number is greater than a recovery generation number, the data is read from the cache. In response to determining at least one of that the data for the storage location is not in the cache and that the generation number is not greater than the recovery generation number, the data is read from one of the production volume and a backup volume based on a value of an indicator for the storage location in the production target data structure.

Abstract: A determination is made that a point-in-time copy of a consistency group of a production volume has to be stored in a backup storage that is configured to store a plurality of point-in-time copies generated at a plurality of time instants. An extent of a thin provisioned volume of a highest storage tier of a tiered storage is allocated to store the point-in-time copy of the consistency group. A process is initiated for storing the point-in-time copy of the consistency group to the extent of the highest storage tier of the tiered storage.

Abstract: Consistency groups are asynchronously copied to a remote computational device, from a local computational device, wherein point in time copy operations are performed at the local computational device while the consistency groups are being asynchronously copied to the remote computational device. Indicators are stored at the remote computational device to identify those point in time copy operations that are to be restored as part of a recovery operation performed at the remote computational device in response to a failure of the local computational device.

Abstract: Provided are a computer program product, system, and method for copying data from multiple point-in-time copies to a log storage to use to roll-back a source storage managing point-in-time copies of a source storage. A plurality of point-in-time copies of a source storage at different point-in-times are established. In response to receiving writes to the source storage after establishing each of the point-in-time copies, point-in-time data in the source storage is copied, before being updated by the received writes, to a log storage, wherein the log storage stores point-in-time data for multiple of the point-in-time copies. The log storage is used to roll-back the source storage to a selected point-in-time of one of the point-in-time copies.

Abstract: A method for accelerating transaction execution across geographically dispersed clusters is disclosed. In one embodiment, such a method includes receiving a request to read data in a data replication system comprising a primary storage system and a secondary storage system in a synchronous mirroring relationship with the primary storage system. The method determines whether at least one of the following conditions is true: (1) the secondary storage system is closer from a communication standpoint; and (2) a high speed communication technology is available to communicate with the secondary storage system that is not available to communicate with the primary storage system. In the event either of the conditions is true, the method directs the request to the secondary storage system. In the event neither of the conditions is true, the method directs the request to the primary storage system. A corresponding system and computer program product are also disclosed.

Abstract: Provided are techniques for determining which target is most ahead in a multi-target mirroring environment between data from a consistent synchronous mirror copy operation and data from a consistent asynchronous mirror copy operation. It is determined that data is to be retrieved from one of a sync secondary storage of a sync secondary storage controller and an async secondary storage of an async secondary storage controller. Then, it is determined which one of data of a consistent synchronous mirror copy operation on the sync secondary storage and data of a consistent asynchronous mirror copy operation on the async secondary storage is a most current copy of the data. The most current copy of the data is retrieved and used for further processing.

Abstract: Provided are a computer program product, system, and method for using a space release data structure to indicate tracks to release for a space release command to release space of tracks in a consistency group being formed. A space release command is received to free a release space of tracks in a source storage or target storage while transferring changed data in a consistency group to a target storage. A space release data structure is created indicating for each track of the tracks in the release space whether to release or not release the track. The space release data structure is initialized to indicate that each of the tracks is to be released. The tracks in the space release data structure are indicated to be released after the consistency group has completed.

Abstract: Provided are a computer program product, system, and method for processing a space release command when mirroring data at a source storage to a target storage. A space release command is received to free a release space in the source storage while transferring changed data in a consistency group. A determination is made as to whether a transfer time to transfer remaining consistency group data in the consistency group for the release space that has not been transferred exceeds a response time to process a space release command. The remaining consistency group data in the release space is transferred to the target storage in response to determining that the transfer time does not exceed the response time. The release space for the space release command is freed in response to transferring the consistency group data in the release space to the target storage.

Abstract: Provided are a computer program product, system, and method for using a forward log storage and backward log storage to recover a storage to a forward or backward point-in-time. In response to receiving writes to source data after establishing point-in-time copies, point-in-time data of the source data is copied to a backward log storage storing point-in-time data for multiple of the point-in-time copies. The point-in-time data in the backward log storage is applied to a recovery source data to roll-back the source data to a backward point-in-time of one of the point-in-time copies. Before applying the point-in-time data from the backward log storage, point-in-time data in the recovery source data, is copied to a forward log storage. The point-in-time data in the forward log storage is applied to the recovery source data to roll forward the recovery source data to a forward point-in-time subsequent to the backward point-in-time.

Abstract: In one embodiment, a local copy target is also a local primary of an incomplete consistency group of an ongoing asynchronous mirror relationship. Completion of the consistency group is facilitated notwithstanding that the local copy operation was initiated after the consistency group was initiated. In one aspect, asynchronous data mirroring logic, prior to the overwriting of existing data of the target, reads the existing data of the target for purposes of mirroring the read data to a remote secondary target of the consistency group. As a result, existing data of the local copy target which is also a local primary source of the consistency group, may be safely overwritten. Other features and aspects may be realized, depending upon the particular application.

Abstract: Provided are techniques for performing a recovery copy command to create a recovery volume for a consistency group. In response to receiving a recovery copy command, a recovery copy data structure is created with indicators for storage locations and a recovery target data structure is created with indicators for storage locations. In response to receiving a write operation for a storage location to a cache on a host for a recovery volume, while the recovery copy command is being processed, it is determined that data is to be staged to the cache and, based on a value of an indicator in the recovery copy data structure for the storage location and a value of an indicator in the recovery target data structure for the storage location, the data is staged from one of the production volume, the recovery volume, and a backup volume.

Abstract: One general aspect of asynchronous local and remote generation of consistent point-in-time snap copies in consistency groups in accordance with the present description, is directed to receiving a local-remote pair point-in-time snap copy establish command to establish a local point-in-time snap copy in a local data storage system, and a remote point-in-time snap copy in a remote data storage system. In one aspect, establishment of the remote point-in-time snap copy relationship may be delayed as a function of the state of a consistency group formation process upon receipt of the local-remote pair point-in-time snap copy establish command. As a result, consistency of the local-remote pair of point-in-time snap copies may be realized, notwithstanding an asynchronous relationship between the local and remote storage systems. Other features and aspects may be realized, depending upon the particular application.

Abstract: A method for efficiently managing extents of backup volumes in a tiered storage system is disclosed. In one embodiment, such a method includes identifying a lifespan associated with a backup volume. The lifespan indicates how long extents of the backup volume are retained in a tiered storage system before being released. The method further assigns a temperature value to the extents that determines where the extents are stored in the tiered storage system. The method utilizes the lifespan to determine the temperature value, where the temperature value is inversely proportional to the lifespan. The method places the extents on tiers of the tiered storage system in accordance with their temperature value, such that higher temperature extents are placed on higher tiers of the tiered storage system, and lower temperature extents are placed on lower tiers of the tiered storage system. A corresponding system and computer program product are also disclosed.

Abstract: Methods and systems for releasing space on a secondary storage device for resynchronization are provided. A system for releasing space on a secondary storage device for resynchronization includes a suspension detection module that determines that the relationship between a primary computing device and a secondary computing device is suspended. The system also includes a relationship resumption module that determines that the relationship between the primary computing device and a secondary computing device is resumed. The system further includes an extent release module that directs the secondary computing device to release extents in a secondary storage device of the secondary computing device that correspond to free extents in a primary storage device of the primary computing device. Additionally, the system includes a synchronization module that synchronizes data stored on the secondary storage device and the primary storage device.

Abstract: A method for accelerating transaction execution across geographically dispersed clusters is disclosed. In one embodiment, such a method includes receiving a request to read data in a data replication system comprising a primary storage system and a secondary storage system in a synchronous mirroring relationship with the primary storage system. The method determines whether at least one of the following conditions is true: (1) the secondary storage system is closer from a communication standpoint; and (2) a high speed communication technology is available to communicate with the secondary storage system that is not available to communicate with the primary storage system. In the event either of the conditions is true, the method directs the request to the secondary storage system. In the event neither of the conditions is true, the method directs the request to the primary storage system. A corresponding system and computer program product are also disclosed.

Abstract: Provided are a computer program product, system, and method for releasing space allocated to a space efficient target storage in a copy relationship with a source storage. Source and target copy relationships indicate source data in the source storage to copy to target data in the target storage. The source copy relationship indicates source data that need to be copied to the target data before being updated, and the target copy relationship indicates target data tracks updated with data copied from corresponding source data. An operation is initiated that results in terminating the source and target copy relationships. Space allocated to the target data for the source and target copy relationships is released in response to determining that the target storage comprises the space efficient storage. The source and target copy relationships are removed.

Abstract: Provided are techniques for performing a recovery copy command to restore a safeguarded copy backup to a production volume. In response to receiving a recovery copy command, a production target data structure is created. A read operation is received for data for a storage location. In response to determining that the data for the storage location is in a cache of a host and a generation number is greater than a recovery generation number, the data is read from the cache. In response to determining at least one of that the data for the storage location is not in the cache and that the generation number is not greater than the recovery generation number, the data is read from one of the production volume and a backup volume based on a value of an indicator for the storage location in the production target data structure.

Abstract: Methods and systems for releasing space on a secondary storage device for resynchronization are provided. A system for releasing space on a secondary storage device for resynchronization includes a suspension detection module that determines that the relationship between a primary computing device and a secondary computing device is suspended. The system also includes a relationship resumption module that determines that the relationship between the primary computing device and a secondary computing device is resumed. The system further includes an extent release module that directs the secondary computing device to release extents in a secondary storage device of the secondary computing device that correspond to free extents in a primary storage device of the primary computing device. Additionally, the system includes a synchronization module that synchronizes data stored on the secondary storage device and the primary storage device.