Abstract: A method for converting from one asynchronous data replication technology to another is disclosed herein. In one embodiment, such a method includes utilizing a first asynchronous data replication technology to asynchronously replicate data from a primary volume to a secondary volume. The method initiates, at time T1, tracking of post-T1 changes to the primary volume and waits for all pre-T1 changes to the primary volume to be propagated to the secondary volume. When all pre-T1 changes have been propagated to the secondary volume, the method suspends operation of the first asynchronous data replication technology and replicates all post-T1 changes from the primary volume to the secondary volume. The method further sets up and initiates a second asynchronous data replication technology to asynchronously replicate data from the primary volume to the secondary volume. A corresponding system and computer program product are also disclosed herein.

Abstract: Provided are a computer program product, system, and method for determining modified tracks to destage during a cache scan. A cache scan is initiated at a time interval to determine modified tracks to destage from a cache to the first or second storage. A modified track is processed during the cache scan. The modified track is destaged to the first storage in response to the modified track stored in the first storage. A determination is made as to whether there was a host write to the second storage since a previous cache scan in response to the modified track stored in the second storage. The modified track is destaged to the second storage in response to determining that there was a host write to the second storage since the previous cache scan.

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 determining modified tracks to destage during a cache scan. A cache scan is initiated at a time interval to determine modified tracks to destage from a cache to the first or second storage. A modified track is processed during the cache scan. The modified track is destaged to the first storage in response to the modified track stored in the first storage. A determination is made as to whether there was a host write to the second storage since a previous cache scan in response to the modified track stored in the second storage. The modified track is destaged to the second storage in response to determining that there was a host write to the second storage since the previous cache scan.

Abstract: A method for converting from one asynchronous data replication technology to another is disclosed herein. In one embodiment, such a method includes utilizing a first asynchronous data replication technology to asynchronously replicate data from a primary volume to a secondary volume. The method initiates, at time T1, tracking of post-T1 changes to the primary volume and waits for all pre-T1 changes to the primary volume to be propagated to the secondary volume. When all pre-T1 changes have been propagated to the secondary volume, the method suspends operation of the first asynchronous data replication technology and replicates all post-T1 changes from the primary volume to the secondary volume. The method further sets up and initiates a second asynchronous data replication technology to asynchronously replicate data from the primary volume to the secondary volume. A corresponding system and computer program product are also disclosed herein.

Abstract: A method to more efficiently utilize data structures in an asynchronous data replication system is disclosed. In one embodiment, such a method includes maintaining, in memory of a primary storage system, a set of data structures for mirroring updates from the primary storage system to a secondary storage system. Each data structure has a status of either active or inactive. The method further establishes an upper threshold and lower threshold for each data structure. The method receives, into active data structures, updates that need to be mirrored to the secondary storage system. When updates in each of the active data structures reaches the upper threshold, the method activates a deactivated data structure. When updates in an active data structure fall below the lower threshold, the method deactivates and drains the data structure. A corresponding system and computer program product are also disclosed.

Abstract: A method for correcting data inconsistency in an asynchronous data replication environment is disclosed. In one embodiment, such a method includes detecting an error on a secondary track of a secondary volume, wherein the secondary volume is in a mirroring relationship with a primary volume. In response to detecting the error, the method flags the secondary track as “temporarily inconsistent.” The method then issues a command to read a corresponding primary track from the primary volume, records a time when the primary track was read, and mirrors the primary track and time to the secondary volume. The method then applies, to the secondary track, updates to the secondary track having a timestamp earlier than the time, and applies the primary track to the secondary track. The method then unflags the secondary track as “temporarily inconsistent.” A corresponding system and computer program product are also disclosed.

Abstract: A method for auditing data consistency in an asynchronous data replication environment is disclosed. In one embodiment, such a method includes copying, at a primary storage system, a primary data track and recording a time that the primary data track was copied. The method replicates the primary data track and associated time from the primary storage system to a secondary storage system. The method applies, to a corresponding secondary data track at the secondary storage system, all updates received for the secondary data track that have a timestamp prior to the time. The method then reads the secondary data track at the secondary storage system after the updates have been applied, and compares the secondary data track to the primary data track. If the secondary data track does not match the primary data track, the method records an error. A corresponding system and computer program product are also disclosed.

Abstract: In one embodiment of the present description, mirroring is provided for a pair of storage units in bidirectional synchronous mirror relationships, and a tertiary storage unit. The mirroring includes multi-target mirroring to write updates written to the first storage unit to both the second storage unit and to a third storage unit. Similarly, for updates written to the second storage unit, multi-target mirroring is employed to write those to both the first storage unit and to the third storage unit. Other aspects are described.

Abstract: A computer-implemented method according to one embodiment includes receiving indication of a failure event at a primary location having a primary data storage volume. In response to receiving the indication of the failure event, data is restored in a secondary data storage volume located at a secondary location remote from the primary location. The restored data is copied to a supplemental data storage volume. A first set of data updates intended for the primary data storage volume are tracked using the supplemental data storage volume. A second set of data updates performed at the secondary data storage volume are tracked. The second set of tracked data updates is merged with the first set of tracked data updates and transitioned to the primary data storage volume in response to the primary data storage volume becoming available. An instruction is sent to resume data updates at the primary data storage volume.

Abstract: A method for auditing data consistency in an asynchronous data replication environment is disclosed. In one embodiment, such a method includes copying, at a primary storage system, a primary data track and recording a time that the primary data track was copied. The method replicates the primary data track and associated time from the primary storage system to a secondary storage system. The method applies, to a corresponding secondary data track at the secondary storage system, all updates received for the secondary data track that have a timestamp prior to the time. The method then reads the secondary data track at the secondary storage system after the updates have been applied, and compares the secondary data track to the primary data track. If the secondary data track does not match the primary data track, the method records an error. A corresponding system and computer program product are also disclosed.

Abstract: A method for correcting data inconsistency in an asynchronous data replication environment is disclosed. In one embodiment, such a method includes detecting an error on a secondary track of a secondary volume, wherein the secondary volume is in a mirroring relationship with a primary volume. In response to detecting the error, the method flags the secondary track as “temporarily inconsistent.” The method then issues a command to read a corresponding primary track from the primary volume, records a time when the primary track was read, and mirrors the primary track and time to the secondary volume. The method then applies, to the secondary track, updates to the secondary track having a timestamp earlier than the time, and applies the primary track to the secondary track. The method then unflags the secondary track as “temporarily inconsistent.” A corresponding system and computer program product are also disclosed.

Abstract: A computer-implemented method, according to one embodiment, includes: using a supplemental data storage volume at a secondary location to track a first set of data updates to a primary data storage volume at a primary location in response to a failure event at the primary location; retrieving a second set of tracked data updates to the primary data storage volume stored in a secondary data storage volume at the secondary location; merging the second set of tracked data updates into the first set of tracked data updates in the supplemental data storage volume; and transitioning the merged data updates from the supplemental data storage volume at the secondary location to the primary data storage volume at the primary location. Other systems, methods, and computer program products are described in additional embodiments.

Abstract: In one general embodiment, a computer-implemented method includes using a supplemental data storage volume at a secondary location to track a first set of data updates to a primary data storage volume at a primary location in response to a failure event at the primary location. A second set of tracked data updates, which are updates to the primary data storage volume stored in a secondary data storage volume at the secondary location, are retrieved. The second set of tracked data updates is merged into the first set of tracked data updates in the supplemental data storage volume. The merged data updates are transitioned from the supplemental data storage volume at the secondary location to the primary data storage volume at the primary location. The secondary data storage volume is used to track further data updates to the primary data storage volume made at the primary location.

Abstract: A computer-implemented method according to one embodiment includes receiving indication of a failure event at a primary location having a primary data storage volume. In response to receiving the indication of the failure event, data is restored in a secondary data storage volume located at a secondary location remote from the primary location. The restored data is copied to a supplemental data storage volume. A first set of data updates intended for the primary data storage volume are tracked using the supplemental data storage volume. A second set of data updates performed at the secondary data storage volume are tracked. The second set of tracked data updates is merged with the first set of tracked data updates and transitioned to the primary data storage volume in response to the primary data storage volume becoming available. An instruction is sent to resume data updates at the primary data storage volume.

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: A method to more efficiently utilize sidefiles in an asynchronous data replication system is disclosed. In one embodiment, such a method includes maintaining, in memory of a primary storage system, a set of sidefiles for mirroring record sets from the primary storage system to a secondary storage system. Each sidefile has a status of either active or inactive. The method further establishes an upper threshold and lower threshold for each sidefile. The method receives, into active sidefiles, record sets that need to be mirrored to the secondary storage system. When record sets in each of the actives sidefiles reaches the upper threshold, the method activates a deactivated sidefile. When record sets in an active sidefile fall below the lower threshold, the method deactivates and drains the sidefile. A corresponding system and computer program product are also disclosed.

Abstract: A method to more efficiently utilize data structures in an asynchronous data replication system is disclosed. In one embodiment, such a method includes maintaining, in memory of a primary storage system, a set of data structures for mirroring updates from the primary storage system to a secondary storage system. Each data structure has a status of either active or inactive. The method further establishes an upper threshold and lower threshold for each data structure. The method receives, into active data structures, updates that need to be mirrored to the secondary storage system. When updates in each of the active data structures reaches the upper threshold, the method activates a deactivated data structure. When updates in an active data structure fall below the lower threshold, the method deactivates and drains the data structure. A corresponding system and computer program product are also disclosed.

Abstract: A method to more efficiently utilize sidefiles in an asynchronous data replication system is disclosed. In one embodiment, such a method includes maintaining, in memory of a primary storage system, a set of sidefiles for mirroring record sets from the primary storage system to a secondary storage system. Each sidefile has a status of either active or inactive. The method further establishes an upper threshold and lower threshold for each sidefile. The method receives, into active sidefiles, record sets that need to be mirrored to the secondary storage system. When record sets in each of the actives sidefiles reaches the upper threshold, the method activates a deactivated sidefile. When record sets in an active sidefile fall below the lower threshold, the method deactivates and drains the sidefile. A corresponding system and computer program product are also disclosed.

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.