International Business Machines Corporation

Robert Nelson Crockett

Gregory E McBride

Ronald Maynard Kern

David Michael Shackelford

William Frank Micka

Alan George McClure

Warren Keith Stanley

Eduard Aaron Diel

Donald Reynold Blea

Lisa Joan Gundy

Robert Wesley Shomler

Nadim P Shehab

Robert Wagner

Robert Frederic Kern

Stephen C West

Michael W Pousson, Jr

Richard E Norris

Arnold G Miller

Debra L Jaworski

A computer implemented method includes the steps of establishing a plurality of storage control sessions, wherein each storage control session associates at least one primary storage controller and at least one secondary storage controller with a predetermined path through a data transport network that interconnects the primary and secondary storage controllers; identifying storage control sessions that have data available to be transferred from primary storage controllers to secondary storage controllers; accumulating available data for each session and determining transfer time through the network for each data element to estimate prospective bandwidth utilization; and determining, for a predetermined time interval, whether transferring the available data would fully occupy available bandwidth of the data transport network for the predetermined time interval. When available bandwidth would be fully occupied, the available data accumulated during predetermined time intervals prior to the predetermined time interval in which fully occupied bandwidth was detected is transferred.

Optimizing data transfer across multiple asynchronous data replication sessions using shared bandwidth

When the mirrored point in time copy fails, at that point in time all the data for making the source and target of the point in time copy consistent is available on secondary volumes at disaster recovery site. The data for the source and target of the failed point in time copy are logically and physically equal at that point in time. This logical relationship can be maintained, and protected against ongoing physical updates to the affected tracks on the source secondary volume, by first reading the affected tracks from the source secondary volume, copying the data to the target secondary volume, and then writing the updated track to the source secondary volume.

Resolving failed mirrored point-in-time copies with minimum disruption

A computer-implemented method, carried out by one or more processors, for a modified asynchronous replication session. In an embodiment, the method comprises the steps of acquiring a lock on a volume configuration, where the lock prevents changes to the volume configuration between a first volume and a second volume at a remote site. Internal control block information is updated, where the update includes at least a volume serial number of the first volume matching a volume serial number of the second volume. Responsive to updating internal control block information, the acquired lock is released to allow changes to the volume configuration.

High availability protection for asynchronous disaster recovery

Provided are a method, system, and program for consolidating session information for a cluster of sessions in a coupled session environment. Information for each of a plurality of sessions comprising a cluster is stored in a memory of a processor session. Each session associates at least one primary system and at least one secondary system, wherein within each session, updates are copied from the at least one primary system to the at least one secondary system. The session information in the memory for the plurality of sessions is processed to generate consolidated session information for the cluster based on the session information for the sessions in the cluster. The consolidated session information for the cluster is written to a master data set maintaining information for sessions.

Consolidating session information for a cluster of sessions in a coupled session environment

Provided are an article of manufacture, method, and system for using multiple sidefiles to buffer writes to primary storage volumes to transfer to corresponding secondary storage volumes in a mirror relationship. Information is provided on a mirror relationship for primary storage volumes and corresponding secondary storage volumes, wherein writes to the primary storage volumes are transferred to the secondary storage volumes according to the mirror relationship. A plurality of sidefiles are associated with the primary storage volumes in the mirror relationship. A write is received to one of the primary storage volumes in the mirror relationship. One of the sidefiles associated with the primary storage volume for which the write is received is selected and the write is buffered in the selected sidefile. Writes to the primary storage volumes buffered in the sidefiles are transferred to the corresponding secondary storage volumes.

Using multiple sidefiles to buffer writes to primary storage volumes to transfer to corresponding secondary storage volumes in a mirror relationship

Disclosed is an article of manufacture, system, and program for determining device suspension and device blocking. Local session cache usage and residual counts are compared against limit values associated with that session, wherein the limit values comprise a device blocking count, a device blocking percent, a suspend count, and a suspend percent for the local session. If a cache in trouble condition is detected based on the comparison, the cache in trouble condition is processed to determine whether one or more volumes are to be blocked or suspended.

Method, system, and program for improved device blocking and suspension

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.

Synchronization and resynchronization of loosely-coupled copy operations between a primary and a remote secondary DASD volume under concurrent updating

Backup storage is resynchronized to primary storage, ensuring that any new updates received during resynchronization are applied in the proper order relative to resynchronization data. Under normal operations, a data mover mirrors data stored in primary storage to backup storage. If an error condition arises, preventing mirroring, the data mover stores newly received data in primary storage without mirroring the data to backup storage. The data mover also identifies this data in an update map. When the error condition ends, the data mover performs a static resynchronization process, serving to update the backup storage with the un-mirrored data, identified in the update map. When new data is received during static resynchronization, a dynamic resynchronization process is invoked to accurately process the updates. Dynamic resynchronization ensures that newly received data records are copied to backup storage in the proper order (if at all) with respect to versions of the same data being processed by static resynchronization.

System and method for dynamically resynchronizing backup data

Provided is a method, system, and program for releasing storage space in a first and second storage devices. Updates to the first storage device are copied to the second storage device to provide secondary storage for the updates. A first and second tables map data sets to addresses in the first and second storage devices, respectively. A first command is detected to invalidate data sets in the first table. The addresses in the first table comprise virtual addresses, and a third table provides a mapping of the virtual addresses to physical storage locations in the first storage device. A second command is generated to update the second table to invalidate the data sets in the second storage device invalidated in the first table by the first command. A third command is detected to invalidate the virtual addresses in the third table used by the data sets invalidated in the first table to free the physical storage locations in the first storage device pointed to by the invalidated virtual addresses. A fourth command is generated that is directed to the physical storage locations in the second storage device used by the invalidated data sets.

Method, system, and program for discarding data in a storage system where updates to a primary storage device are shadowed in a secondary storage device

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. CONCURRENT UPDATING

Disclosed is a system for maintaining consistency of data across storage devices. A cut-off time value is provided to the system. The system then obtains information on data writes to a first storage device, including information on time stamp values associated with the data writes indicating an order of the data writes to the first storage device. At least one group of data writes having time stamp values earlier in time than the cut-off time value is then formed. The system then transfers the data writes in the groups to a second storage device for storage therein.

Multi-environment data consistency

Disclosed is a system for managing pages in a volatile memory device for data transfer operations between a first storage area and a second storage area. The first storage area is queried to determine a number of data sets to include in a data transfer operation. A number of pages in the volatile memory device needed for the data transfer operation is then determined. A determination is then made as to whether the number of pages needed for the data transfer operation is greater than available fixed pages in a pool of pages. Available fixed pages in the pool are allocated to the data transfer operation after determining that the number of pages needed to process the data transfer operation is less than or equal to the available fixed pages in the pool. Alternatively, after determining that the number of pages needed to process the data transfer operation is greater than the available fixed pages in the pool, all the fixed pages in the pool and additional fixed pages are allocated to the data transfer operation.

Management of fixed pages in memory for input/output operations

A primary data mover monitors both consistency time and idle time in a system that performs continuous, asynchronous, extended remote copying between primary and remote processors, and manages both with accuracy and consistency. The primary data mover detects system activity levels and manages data accuracy for the extended remote copying in both active and idle systems.

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Tucson, AZ, United States of America

Robert Nelson Crockett