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 a computer program product, system, and method for updating change information for current copy relationships when establishing a new copy relationship having overlapping data with the current copy relationships. A first copy relationship indicates changed first source data to copy to first target data. An establish request is processed to create a second copy relationship to copy second source data in to second target data. A second copy relationship is generated, in response to the establish request, indicating data in the second source data to copy to the second target data. A determination is made of overlapping data units in the first source data also in the second target data. Indication is made in the first copy relationship to copy the overlapping data units. The first source data indicated in the first copy relationship is copied to the first target data, including data for the overlapping data units.

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: 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: A request is received to perform a point in time copy operation from a source volume to a space efficient target volume. A controller copies data stored in a group of data storage units, from the source volume to a non-volatile storage, to preserve the point in time copy operation. A background process asynchronously copies the data from the non-volatile storage to the space efficient target volume to commit a physical point in time copy of the data from the source volume to the target volume.

Abstract: A request is received to perform a point in time copy operation from a source volume to a space efficient target volume. A controller copies data stored in a group of data storage units, from the source volume to a non-volatile storage, to preserve the point in time copy operation. A background process asynchronously copies the data from the non-volatile storage to the space efficient target volume to commit a physical point in time copy of the data from the source volume to the target volume.

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: Provided are a computer program product, system, and method for forming a consistency group comprised of volumes maintained by one or more storage controllers. At least one storage controller is caused to perform reservation operations for point-in-time copies of storage units to allocate storage resources and a data structure for a point-in-time copy. Upon successfully completing the reservation operations for all the point-in-time copies, Input/Output (I/O) operations to the storage units of the point-in-time copies are suspended. If I/O operations were successfully suspended at the storage units for all of the point-in-time copies, then suspension of I/O operations is ended I/O operations are allowed to continue at the storage units of the point-in-time copies. The point-in-time copies at the storage units are formed at which the suspension of I/O operations was ended after being successfully suspended. The point-in-time copies are consistent as of a same point-in-time.

Abstract: Provided are a computer program product, system, and method for copying point-in-time data in a storage to a point-in-time copy data location in advance of destaging data to the storage. A point-in-time copy is created to maintain tracks in a source storage unit as of a point-in-time. A source copy data structure indicates tracks in the source storage unit to copy from the storage to a point-in-time data location. An update to write to a source track is received and a determination is made as to whether the source copy data structure indicates to copy the source track from the storage to the point-in-time data location. The update is written to a cache. A copy operation is initiated to copy the source track from the storage to the point-in-time data location asynchronous before the source track is destaged from the cache to the storage unit.

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: Provided are a computer program product, system, and method for performing a remote point-in-time copy to a source and target storages in further mirror copy relationships. Each of a plurality of source copy relationships is from the source storage to one corresponding source copy storage. Each of a plurality of target copy relationships is from the target storage to one corresponding target copy storage, where in each relationship an indicator indicates whether to use a remote first type copy operation. The first type copy operation is used to copy data from the source storage to the target storage and copy data from the source copy storage to the target copy storage for the determined source and target copy relationships having the indicator set. A second type of copy operations is used for source and target relationships not having the indicator set.

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 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: 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: Provided are a computer program product, system, and method for forming a consistency group comprised of volumes maintained by one or more storage controllers. At least one storage controller is caused to perform reservation operations for point-in-time copies of storage units to allocate storage resources and a data structure for a point-in-time copy. Upon successfully completing the reservation operations for all the point-in-time copies, Input/Output (I/O) operations to the storage units of the point-in-time copies are suspended. If I/O operations were successfully suspended at the storage units for all of the point-in-time copies, then suspension of I/O operations is ended I/O operations are allowed to continue at the storage units of the point-in-time copies. The point-in-time copies at the storage units are formed at which the suspension of I/O operations was ended after being successfully suspended. The point-in-time copies are consistent as of a same point-in-time.

Abstract: Provided are a computer program product, system, and method for copying point-in-time data in a storage to a point-in-time copy data location in advance of destaging data to the storage. A point-in-time copy is created to maintain tracks in a source storage unit as of a point-in-time. A source copy data structure indicates tracks in the source storage unit to copy from the storage to a point-in-time data location. An update to write to a source track is received and a determination is made as to whether the source copy data structure indicates to copy the source track from the storage to the point-in-time data location. The update is written to a cache. A copy operation is initiated to copy the source track from the storage to the point-in-time data location asynchronous before the source track is destaged from the cache to the storage unit.

Abstract: Provided are a computer program product, system, and method for using a cascade flag to process a copy relationship having a backward cascade copy relationship. Each of a plurality of copy relationships indicates to copy source data to target data and has a cascade flag. The cascade flag for a forward copy relationship of the copy relationships is set to a first value in response to determining that the source data for the forward copy relationship comprises target data for a backward copy relationship and that a background copy operation specified to copy source data to target data of the backward copy relationship has not completed. The cascade flag for the forward copy relationship is set to a second value in response to determining that the backward copy relationship does not have an uncompleted background copy operation.

Abstract: Provided are a computer program product, system, and method for updating change information for current copy relationships when establishing a new copy relationship having overlapping data with the current copy relationships. A first copy relationship indicates changed first source data to copy to first target data. An establish request is processed to create a second copy relationship to copy second source data in to second target data. A second copy relationship is generated, in response to the establish request, indicating data in the second source data to copy to the second target data. A determination is made of overlapping data units in the first source data also in the second target data. Indication is made in the first copy relationship to copy the overlapping data units. The first source data indicated in the first copy relationship is copied to the first target data, including data for the overlapping data units.

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: 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.