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: 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, 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: 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: 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: 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: 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: Provided are a computer program product, system, and method for using queues corresponding to attribute values associated with units of work to select the units of work to process. A plurality of queues for each of a plurality of attribute types of attributes are associated with the units of work to process, wherein there are queues for different possible attribute values for each of the attribute types. A unit of work to process is received. A determination is made for each of the attribute types at least one of the queues corresponding to at least one attribute value for the attribute type associated with the received unit of work. A record for the received unit of work is added to each of the determined queues.

Abstract: For performing efficient management of tracks in an asynchronous Peer-to-Peer Redundant Copy (PPRC) operation in a computing storage environment, a correct status of a sequential bit is determined by examining a primary cache, where if data being transferred pursuant to the PPRC operation in a primary track remains in the primary cache, the sequential bit setting found therein is used.

Abstract: A method for caching reads in a data replication environment is disclosed. In one embodiment, such a method includes receiving a read request at a primary site of a data replication environment. The method executes the read request at the primary site. In the event data associated with the read request is not already cached at the primary site, the method stores the data in cache at the primary site. The method also notifies a secondary site of the read request at the primary site. This notification may be sent synchronously or asynchronously as time and resources allow. In the event the data is not already cached at the secondary site, the method stores the data in cache at the secondary site. A corresponding system and computer program product are also disclosed.

Abstract: For performing efficient full-stride copy source-to-target operations in a computing storage environment by a processor device, pursuant to a destage operation, a determination is made whether to destage a full stride or one track of data on a target volume by comparing a counted number of modified tracks for the full stride against a predetermined threshold.

Abstract: A first asynchronous mirroring session is initiated to asynchronously copy first primary volumes to first secondary volumes. Point in time copy operations generate a local backup copy from the first primary volumes. Second primary volumes are generated from the local backup copy. A second asynchronous mirroring session is initiated to asynchronously copy the second primary volumes to second secondary volumes.

Abstract: Provided is a method for managing operation requests using different resources. In one embodiment, a first queue is provided for operations which utilize a first resource of a first and second resource. A second queue is provided for operations which utilize the second resource. An operation is queued on the first queue until the first resource is acquired. The first resource is released if the second resource is not also acquired. The operation is queued on the second queue when the first resource is acquired but the second resource is not. In addition, the first resource is released until the operation acquires both the first resource and the second resource.

Abstract: Provided are a computer program product, system, and for data activity tracking in accordance with the present description, in which metadata is read from a storage unit data structure for a storage unit storing data of a plurality of data sets in a plurality of data units of the storage unit. Based upon read metadata, a data set of the storage unit may be classified as one of active and inactive, and if classified as inactive, data units containing data of the inactive classified first data set may be selected. The data of the inactive classified data set may be migrated from the selected data units of a first storage performance tier to a second storage performance tier having a lower level of storage performance than the first storage performance tier. Other aspects of data activity tracking and migration in accordance with the present description are described.

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.