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: 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: 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 method for enabling point-in-time-copy target volumes to be primary volumes in PPRC relationships is disclosed. In one embodiment, such a method includes reserving, on a first storage device, first resources needed to establish a first point-in-time-copy relationship between a first source volume and a first target volume. The method further sends a reservation request to a second storage device to reserve second resources needed to establish, on the second storage device, a second point-in-time-copy relationship between a second source volume and a second target volume. In the event the reservation request is successfully executed, the method establishes the first point-in-time-copy relationship on the first storage device using the first resources, and sends a check-in request to the second storage device to establish the second point-in-time-copy relationship on the second storage device using the second resources. A corresponding system and computer program product are also disclosed.

Abstract: In accordance with one embodiment, asynchronous local and remote generation of consistent first and second point-in-time snap copy volumes provides for generating in a primary system, a first point-in-time snap copy volume of a primary volume of the primary system, and generating in a secondary system, a second point-in-time snap copy volume utilizing a secondary volume in the secondary system. Synchronizing logic synchronizes the first and second point-in-time snap copy volumes to be consistent with each other as of a particular point-in-time notwithstanding an asynchronous mirror relationship between the primary volume of the primary system and the secondary volume of the secondary system. Other features and aspects may be realized, depending upon the particular application.

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 method for releasing storage space in a space-efficient secondary volume includes placing a first lock on a free-space data structure stored on the space-efficient secondary volume. The method reads a copy of the free-space data structure into memory while the first lock is in place, and releases the first lock. The method then analyzes the copy to determine which storage elements in the space-efficient secondary volume are not being used. The method then places a second lock on the free-space data structure and, while the second lock is in place, analyzes the free-space data structure to determine which storage elements had their usage status change during analysis of the copy. The method then releases storage elements in the space-efficient secondary volume that are not being used and releases the second lock. A corresponding system and computer program product are also disclosed.

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: A method, system and computer-usable medium are disclosed for improved point-in-time copying of data within an asynchronous data mirroring environment comprising: receiving a request to initiate an asynchronous data mirroring operation associated with a first point-in-time copying process; processing a first set of establish data to generate a point-in-time establish reservation, the first set of establish data associated with the first point-in-time copying process establish; using the point-in-time establish reservation to generate a second set of establish data if the second point-in-time copying process can be performed; using the second set of establish data to initiate a second point-in-time copying process; and, tracking establish operations in progress between the first point-in-time copying process and the second point-in-time copying process.

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: A computational device receives a command to activate a time lock for a data set. In response to receiving the command to activate the time lock for the data set, a point in time copy of the data set is generated to allow write operations to be performed even if the time lock is activated.

Abstract: Provided are a method, system, and computer program product in which a computational device stores a data structure that includes identifications of a plurality of volumes and identifications of one or more time locks associated with each of the plurality of volumes. The data structure is indexed into, to determine whether an input/output (I/O) operation from a host with respect to a volume is to be permitted.

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 offloading processing of writes to determine malicious data from a first storage system to a second storage system. Write data for a first storage is cached in a first cache in the first storage system and copied to a second cache in the second storage system. The second storage system determines whether the copy of the write data comprises random data according to a randomness criteria. The second storage system returns a message to the first storage system indicating that the write data comprises malicious data if random or not malicious data if not random. The first storage system destages the write data in the first cache if the message indicates not malicious data or processes the write data in the first cache as malicious data if the message indicates malicious data.

Abstract: Provided are a computer program product, system, and method for determining whether to destage write data in cache to storage based on whether the write data has malicious data. Write data for a storage is cached in a cache. A determination is made as to whether the write data in the cache comprises random data according to a randomness criteria. The write data in the cache to the storage in response to determining that the write data does not comprise random data according to the randomness criteria. The write data is processed as malicious data after determining that the write data comprises random data according to the randomness criteria.

Abstract: A method for releasing storage space in asynchronously mirrored space-efficient secondary volumes is disclosed. In one embodiment, such a method includes reading a first copy of a free-space data structure stored on a space-efficient secondary volume. The free-space data structure tracks the usage status of storage elements in the space-efficient secondary volume. The method analyzes the first copy to determine which storage elements in the space-efficient secondary volume are not being used. Upon completion of a consistency group on the space-efficient secondary volume, the method reads a second copy of the free-space data structure and compares the first copy to the second copy to determine which storage elements had their usage status change during analysis of the first copy. The method releases storage elements in the space-efficient secondary volume that are not being used. A corresponding system and computer program product are also disclosed.

Abstract: Provided are a computer program product, system, and method for managing health conditions to determine when to restart replication after a swap triggered by a storage health event. A determination is made of a health condition with respect to access to a first storage that triggers a swap operation. The swap operation redirects host Input/Output (I/O) requests to data from a first server to a second server in response to determining the health condition. After the swap operation the I/O requests are directed to the second server and a second storage. The second server is instructed to mirror data in the second storage to the first server to store in the first storage in response to determining that the health condition is resolved.

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 a computer program product, system, and method for after swapping from a first storage to a second storage, mirroring data from the second storage to the first storage for data in the first storage that experienced data errors. A swap operation redirects host Input/Output (I/O) requests to data from the first server to the second server in response to a health condition at the first server. A determination is made of data errors with respect to data in the first storage that experienced data errors. The second server is instructed to mirror data in the second storage to the first server including data for the data in the first storage that experienced the data errors to store in the first storage in response to determining that the first server is available for the data mirroring operations.

Abstract: Provided are a computer program product, system, and method for after swapping from a first storage to a second storage, mirroring data from the second storage to the first storage for data in the first storage that experienced data errors. A swap operation redirects host Input/Output (I/O) requests to data from the first server to the second server in response to a health condition at the first server. A determination is made of data errors with respect to data in the first storage that experienced data errors. The second server is instructed to mirror data in the second storage to the first server including data for the data in the first storage that experienced the data errors to store in the first storage in response to determining that the first server is available for the data mirroring operations.