Abstract: Techniques are provided for performing a copy operation. An instant virtual copy operation is issued from a first portion of data to a primary mirroring portion of data, wherein the primary mirroring portion of data corresponds to a secondary mirroring portion of data, and wherein the primary mirroring portion of data and the secondary mirroring portion of data are in a mirroring relationship. The mirroring relationship is transitioned to a duplex pending state in response to determining that the mirroring relationship is in a full duplex state. When the mirroring relationship is in a duplex pending state, each block of data involved in the instant virtual copy operation is transferred from the primary mirroring portion of data to the secondary mirroring portion of data.

Abstract: An apparatus, system, and method are disclosed for detecting mismatches in a mirror volume. A receive module receives a start indicator from a primary storage system. The start indicator includes a starting location of a first block to be modified on a track in a secondary storage system. The first block corresponds to an identically located first block of a modified record in the primary storage system. The tracks the first blocks on the primary and secondary storage systems each comprise irregular count key data (“CKD”) tracks. A compare module compares the first block location indicated by the start indicator with block locations listed in track metadata. The track metadata describes user records on the irregular CKD tracks of the secondary storage system. An alert module generates an alert in response to the first block not aligning with a beginning block of a record on the secondary storage system.

Abstract: A method and system for updating status information in a persistent storage. The method comprises the steps of defining a table in persistent storage (NVS) for holding information about changes to the status information; and when that status information is changed, making an entry in the table to record the changed information. A task is initialized to update the information on the disk drive. This updating is done by (i) checking the table to determine if any changes have been recorded in the persistent storage, and (ii) if any changes have been recorded in the persistent storage, then copying the status information from the persistent storage to the disk drive.

Abstract: A method for assuring consistency between a primary volume and a remote secondary volume wherein a host CPU manages track-to-track transfers using loosely-coupled, storage control unit mediated, data paths. The method includes initial volume synchronization in which concurrent updates to primary tracks are serialized by the copy progression at the secondary volume according to address. The method further includes volume resynchronization in the event of extrinsic error, fault, or the like in which the status of primary tracks updated during a volume suspension interval utilize bit maps to determine status of tracks unmodified during the suspension interval, and updated tracks and timestamps in addition to addresses. The bit maps and timestamps preserve the most recent version copy order of the tracks on the secondary volume.

Abstract: A method and system for updating status information in a persistent storage. The method comprises the steps of defining a table in persistent storage (NVS) for holding information about changes to the status information; and when that status information is changed, making an entry in the table to record the changed information. A task is initialized to update the information on the disk drive. This updating is done by (i) checking the table to determine if any changes have been recorded in the persistent storage, and (ii) if any changes have been recorded in the persistent storage, then copying the status information from the persistent storage to the disk drive.

Abstract: A method for assuring consistency between a primary volume and a remote secondary volume wherein a host CPU manages track-to-track transfers using loosely-coupled, storage control unit mediated, data paths. The method includes initial volume synchronization in which concurrent updates to primary tracks are serialized by the copy progression at the secondary volume according to address. The method further includes volume resynchronization in the event of extrinsic error, fault, or the like in which the status of primary tracks updated during a volume suspension interval utilize bit maps to determine status of tracks unmodified during the suspension interval, and updated tracks and timestamps in addition to addresses. The bit maps and timestamps preserve the most recent version copy order of the tracks on the secondary volume.

Abstract: A method for assuring consistency between a primary volume and a remote secondary volume wherein a host CPU manages track-to-track transfers using loosely-coupled, storage control unit mediated data paths. The method includes initial volume synchronization in which concurrent updates to primary tracks are serialized by the copy progression at the secondary volume according to address. The method further includes volume resynchronization in the event of extrinsic error, fault, or the like in which bit maps and timestamps are used to determine the status of primary tracks either lost while in flight to the secondary volume or updated during a volume suspension interval. The bit maps and timestamps preserve the most recent version copy order of the tracks on the secondary volume.

Abstract: When a primary data storage subsystem receives updates for local storage and mirroring at a counterpart secondary storage subsystem, the primary subsystem institutes device-specific, fairness-driven update blocking to avoid overrunning the primary subsystem's update buffer with updates destined for any one device. Broadly, the primary subsystem first receives update requests, then logs the updates in an update buffer, then stores the logged updates in primary storage, and finally copies the updates to the secondary storage subsystem. Each update request includes update data and also identifies a targeted logical device, physical device, or other subpart of primary storage. The primary subsystem maintains a counter or other update activity indicator that represents update activity for each storage subpart, such as the number of updates stored in the buffer. For each update request, the primary subsystem determines whether target subpart's update activity exceeds a prescribed level.

Abstract: Disclosed is a system, method, and program for limiting input/output (I/O) requests from an application program to a storage device to facilitate the processing of data in memory. A determination is made as to whether an amount of a set of data in memory exceeds at least one threshold. At least one of multiple paths to the storage device is indicated as blocked to I/O requests from the application program. Each indicated blocked path is available for processing the set of data in memory. An I/O request from the application program is received and a determination is made as to whether the received I/O request intends to access the storage device using one indicated blocked path. The I/O request is denied access to the storage device via the blocked path.

Abstract: A disaster recovery system providing asynchronous remote data shadowing between a primary and a secondary site uses a pair of track arrays for each primary data storage device of a remote copy pair to monitor which record updates are in transit between the primary site and the secondary site. A host processor at the primary site of the disaster recovery system transfers a sequentially consistent order of copies of record updates to the secondary site for back-up purposes. The copied record updates are stored on the secondary data storage devices which form remote copy pairs with the primary data storage devices at the primary site. One track array, the active track array, is used to set elements according to which tracks on the primary data storage device receive record updates from the host processor at the primary site.

Abstract: A data storage system provides disaster recovery capability by asynchronously transmitting record updates to a secondary site in sequence consistent order. Such record updates are stored at a primary site in a cache memory of a storage controller. A circular queue is created having a head pointer for locating a first (or oldest) record update with subsequent record updates of a track being linked therefrom in sequence consistent order. A tail pointer of the circular queue points to the last record update. A counter field is provided in a track slot header for counting a number of updated records in the track and hence the circular queue. When a data mover in the host processor at the primary site reads record updates for transmission to the secondary site, the data mover starts with the record update pointed to by the head pointer such that the data mover moves through the circular queue (and hence the record updates) in a backward chain fashion.