Abstract: A computer-implemented method according to one embodiment includes identifying data to be transferred as part of a point-in-time snapshot copy operation; setting a data consistency application in an idle state; marking the data while the data consistency application is in the idle state; restarting the data consistency application; identifying, by the data consistency application, the marked data; creating, by the data consistency application, a consistency group including the marked data; and performing replication of the consistency group.

Abstract: A computer-implemented method according to one embodiment includes receiving a request to withdraw a point-in-time snapshot copy operation being implemented by a data consistency application; in response to determining that the data consistency application is creating a current consistency group, maintaining the withdrawal request while allowing the creation of the current consistency group by the data consistency application; and in response to determining that the data consistency application is idle, preventing a formation of a new consistency group by the data consistency application during the withdrawal of the point-in-time snapshot copy operation.

Abstract: Provided are I/O request type specific cache directories in accordance with the present description. In one embodiment, by limiting track entries of a cache directory to a specific I/O request type, the size of the cache directory may be reduced as compared to general cache directories for I/O requests of all types, for example. As a result, look-up operations directed to such smaller size I/O request type specific cache directories may be completed in each directory more quickly. In addition, look-ups may frequently be successfully completed after a look-up of a single I/O request type specific cache directory, improving the speed of cache look-ups and providing a significant improvement in system performance. Other aspects and advantages are provided, depending upon the particular application.

Abstract: A method for improving asynchronous data replication between a primary storage system and a secondary storage system is disclosed. In one embodiment, such a method includes monitoring, in a cache of the primary storage system, unmirrored data elements needing to be mirrored, but that have not yet been mirrored, from the primary storage system to the secondary storage system. The method maintains a regular LRU list designating an order in which data elements are demoted from the cache. The method determines whether a data element at an LRU end of the regular LRU list is an unmirrored data element. In the event the data element at the LRU end of the regular LRU list is an unmirrored data element, the method moves the data element to a transfer-pending LRU list dedicated to unmirrored data elements in the cache. A corresponding system and computer program product are also disclosed.

Abstract: Metadata logic switches selection of a metadata track from multiple available metadata tracks in a volatile cache to fill the selected metadata track in a metadata track selection interval with metadata entries as source tracks of a source volume are copied to a backup volume of a copy relationship. Destage logic destages to storage a deselected metadata track containing metadata entries generated in a prior metadata track selection interval, while the metadata logic continues to generate and fill additional metadata entries in the selected metadata track in a concurrent metadata track selection interval. Other features and aspects may be realized, depending upon the particular application.

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: Provided are a computer program product, system, and method for indicating tracks as erased without deleting data for the tracks. In response to receiving erase commands to erase tracks in the storage, indicating the tracks as erased without performing an erase operation on the tracks subject to the erase command. Data in the storage for the tracks indicated as erased remains in the storage while requests are directed to the tracks indicated as erased. A command is received indicating an operation with respect to a target track. The operation to proceed is permitted with respect to the target track in response to determining that the target track is not indicated as erased. An alternate operation is performed providing a result different from the operation indicated in the command in response to determining that the target track is indicated as erased.

Abstract: Provided are I/O request type specific cache directories in accordance with the present description. In one embodiment, by limiting track entries of a cache directory to a specific I/O request type, the size of the cache directory may be reduced as compared to general cache directories for I/O requests of all types, for example. As a result, look-up operations directed to such smaller size I/O request type specific cache directories may be completed in each directory more quickly. In addition, look-ups may frequently be successfully completed after a look-up of a single I/O request type specific cache directory, improving the speed of cache look-ups and providing a significant improvement in system performance. Other aspects and advantages are provided, depending upon the particular application.

Abstract: A method for improving asynchronous data replication between a primary storage system and a secondary storage system is disclosed. In one embodiment, such a method includes monitoring, in a cache of the primary storage system, unmirrored data elements needing to be mirrored, but that have not yet been mirrored, from the primary storage system to the secondary storage system. The method maintains a regular LRU list designating an order in which data elements are demoted from the cache. The method determines whether a data element at an LRU end of the regular LRU list is an unmirrored data element. In the event the data element at the LRU end of the regular LRU list is an unmirrored data element, the method moves the data element to a transfer-pending LRU list dedicated to unmirrored data elements in the cache. A corresponding system and computer program product are also disclosed.

Abstract: A computer-implemented method according to one embodiment includes receiving a request to withdraw a point-in-time snapshot copy operation being implemented by a data consistency application; in response to determining that the data consistency application is creating a current consistency group, maintaining the withdrawal request while allowing the creation of the current consistency group by the data consistency application; and in response to determining that the data consistency application is idle, preventing a formation of a new consistency group by the data consistency application during the withdrawal of the point-in-time snapshot copy operation.

Abstract: A computer-implemented method according to one embodiment includes determining that a consistency group has not been created within a predetermined period of time; sending a request to create the consistency group, where the request includes an indication that a creation of the consistency group is mandatory; identifying one or more logical storage volumes associated with the request to create the consistency group; marking each of the identified one or more logical storage volumes to indicate that a point-in-time snapshot copy operation is not allowed for the one or more logical storage volumes; creating the consistency group; sending the consistency group from a source site to a destination site; and removing the marking from each of the identified one or more logical storage volumes to indicate that a point-in-time snapshot copy operation is allowed for the one or more logical storage volumes.

Abstract: A computer-implemented method according to one embodiment includes identifying data to be transferred as part of a point-in-time snapshot copy operation; setting a data consistency application in an idle state; marking the data while the data consistency application is in the idle state; restarting the data consistency application; identifying, by the data consistency application, the marked data; creating, by the data consistency application, a consistency group including the marked data; and performing replication of the consistency group.

Abstract: Provided are a computer program product, system, and method for indicating tracks as erased without deleting data for the tracks. In response to receiving erase commands to erase tracks in the storage, indicating the tracks as erased without performing an erase operation on the tracks subject to the erase command. Data in the storage for the tracks indicated as erased remains in the storage while requests are directed to the tracks indicated as erased. A command is received indicating an operation with respect to a target track. The operation to proceed is permitted with respect to the target track in response to determining that the target track is not indicated as erased. An alternate operation is performed providing a result different from the operation indicated in the command in response to determining that the target track is indicated as erased.

Abstract: A computer-implemented method according to one embodiment includes determining that a consistency group has not been created within a predetermined period of time; sending a request to create the consistency group, where the request includes an indication that a creation of the consistency group is mandatory; identifying one or more logical storage volumes associated with the request to create the consistency group; marking each of the identified one or more logical storage volumes to indicate that a point-in-time snapshot copy operation is not allowed for the one or more logical storage volumes; creating the consistency group; sending the consistency group from a source site to a destination site; and removing the marking from each of the identified one or more logical storage volumes to indicate that a point-in-time snapshot copy operation is allowed for the one or more logical storage volumes.

Abstract: A method for improving asynchronous data replication between a primary storage system and a secondary storage system is disclosed. In one embodiment, such a method includes monitoring, in a cache of the primary storage system, unmirrored data elements needing to be mirrored, but that have not yet been mirrored, from the primary storage system to the secondary storage system. The method maintains an LRU list designating an order in which data elements are demoted from the cache. The method determines whether a data element at an LRU end of the LRU list is an unmirrored data element. In the event the data element at the LRU end of the LRU list is an unmirrored data element, the method moves the data element to an MRU end of the LRU list. A corresponding system and computer program product are also disclosed.

Abstract: Provided are a computer program product, system, and method for indicating tracks as erased without deleting data for the tracks. In response to receiving erase commands to erase tracks in the storage, indicating the tracks as erased without performing an erase operation on the tracks subject to the erase command. Data in the storage for the tracks indicated as erased remains in the storage while requests are directed to the tracks indicated as erased. A command is received indicating an operation with respect to a target track. The operation to proceed is permitted with respect to the target track in response to determining that the target track is not indicated as erased. An alternate operation is performed providing a result different from the operation indicated in the command in response to determining that the target track is indicated as erased.

Abstract: Provided are a computer program product, system, and method for performing a failover between a first storage system and a second storage system. Data is synchronized between the first storage system and the second storage system. A failover is performed from the first storage system to the second storage system in response to a failover event at the first storage system while synchronizing the data. A determination is made that a first storage unit of the first storage system is inoperable and that that a second storage unit of the first storage system is operable in response to the failover event. In response to determining that the second storage unit is operable, a resynchronization is initiated to copy updates to a second storage unit of the second storage system mirroring the second storage unit of the first storage system to the second storage unit of the first storage system.

Abstract: A plurality of tracks that are to be copied to a backup volume are aggregated in a container data structure. The plurality of tracks are stored physically contiguously in a single Redundant Array of Independent Disks (RAID) stride. Mapping metadata is updated in the backup volume to indicate how logical tracks of the backup volume correspond to physical tracks stored in the RAID stride.

Abstract: A storage controller configures a plurality of storage tiers. A sub-unit of a storage unit is maintained in a selected storage tier of the plurality of storage tiers, for at least a predetermined duration of time subsequent to an input/output (I/O) request for the sub-unit.

Abstract: Provided are a computer program product, system, and method for replicating tracks from a first storage to a second and third storages. A determination is made of a track in the first storage to transfer to the second storage as part of a point-in-time copy relationship and of a stride of tracks including the target track. The stride of tracks including the target track is staged from the first storage to a cache according to the point-in-time copy relationship. The staged stride is destaged from the cache to the second storage. The stride in the cache is transferred to the third storage as part of a mirror copy relationship. The stride of tracks in the cache is demoted in response to destaging the stride of the tracks in the cache to the second storage and transferring the stride of tracks in the cache to the third storage.