Abstract: In one embodiment, I/O operations may be swapped from an original storage unit to a replacement storage unit in a manner which can reduce or eliminate delays caused by copying of data from the original storage unit to the replacement storage unit. A point-in-time snap copy relationship between the original storage unit and the replacement storage unit of storage locations is established and I/O operations are swapped from the original storage unit to the replacement storage unit. The I/O operations are resumed, accessing the replacement storage unit instead of the original storage unit in the input/output operations issued by the at least one host. Other aspects are described.

Abstract: In one embodiment, I/O operations may be swapped from an original storage unit to a replacement storage unit in a manner which can reduce or eliminate delays caused by copying of data from the original storage unit to the replacement storage unit. A point-in-time snap copy relationship between the original storage unit and the replacement storage unit of storage locations is established and I/O operations are swapped from the original storage unit to the replacement storage unit. The I/O operations are resumed, accessing the replacement storage unit instead of the original storage unit in the input/output operations issued by the at least one host. Other aspects are described.

Abstract: In one embodiment, I/O operations may be swapped from an original storage unit to a replacement storage unit in a manner which can reduce or eliminate delays caused by copying of data from the original storage unit to the replacement storage unit. A point-in-time snap copy relationship between the original storage unit and the replacement storage unit of storage locations is established and I/O operations are swapped from the original storage unit to the replacement storage unit. The I/O operations are resumed, accessing the replacement storage unit instead of the original storage unit in the input/output operations issued by the at least one host. Other aspects are described.

Abstract: In one embodiment, I/O operations may be swapped from an original storage unit to a replacement storage unit in a manner which can reduce or eliminate delays caused by copying of data from the original storage unit to the replacement storage unit. A point-in-time snap copy relationship between the original storage unit and the replacement storage unit of storage locations is established and I/O operations are swapped from the original storage unit to the replacement storage unit. The I/O operations are resumed, accessing the replacement storage unit instead of the original storage unit in the input/output operations issued by the at least one host. Other aspects are described.

Abstract: In one embodiment, I/O operations may be swapped from an original storage unit to a replacement storage unit in a manner which can reduce or eliminate delays caused by copying of data from the original storage unit to the replacement storage unit. A point-in-time snap copy relationship between the original storage unit and the replacement storage unit of storage locations is established and I/O operations are swapped from the original storage unit to the replacement storage unit. The I/O operations are resumed, accessing the replacement storage unit instead of the original storage unit in the input/output operations issued by the at least one host. Other aspects are described.

Abstract: In one embodiment, I/O operations may be swapped from an original storage unit to a replacement storage unit in a manner which can reduce or eliminate delays caused by copying of data from the original storage unit to the replacement storage unit. A point-in-time snap copy relationship between the original storage unit and the replacement storage unit of storage locations is established and I/O operations are swapped from the original storage unit to the replacement storage unit. The I/O operations are resumed, accessing the replacement storage unit instead of the original storage unit in the input/output operations issued by the at least one host. Other aspects are described.

Abstract: An apparatus, system, and method are disclosed for determining prefetch data. A start module communicates a start of a target software process to a storage device. A learning module learns data blocks accessed for the target software process. In one embodiment, a prefetch module prefetches the learned data blocks in response to the start of the target software process. An end module communicates the end of the target software process to the storage device. In one embodiment, the prefetch module terminates prefetching data blocks and the learning module terminates learning the data blocks accessed for the target software process in response to the end module's communication of the end of the target software process.

Abstract: A method is disclosed for reliably updating a data group in a read-before-write data replication environment. The method reliably updates the data group by receiving an updated data group sent from a first storage medium to a second storage medium, comparing the updated data group with a previous data group previously existing on the second storage medium and writing the updated data group to the second storage medium. The read-before-write and differencing method disclosed maintain reliability by storing multiple copies of changes made to the second storage medium during and after the write process.

Abstract: Data and metadata are generated in a computational device, wherein the generated data is stored in a first physical storage device coupled to the computational device, and wherein the generated metadata is stored transiently in the computational device. The data and the metadata are replicated to a second physical storage device. The replicated data and the replicated metadata in the second physical storage device are used to recover from a failure of at least one of the computational device and the first physical storage device.

Abstract: A network component useful in tracking write activity by writing logs containing write address information is described. The tracking component may be used in networked systems employing data mirrors to record data block addresses written to a primary storage volume during the time a data mirror is unavailable. The tracking component can be available to any network originating node, and may therefore track write activity on multiple volumes. At the time a data mirror is reconstructed, the log written may be used to construct a list of block addresses pointing to locations on a primary storage volume wherein data differs from a secondary storage volume member of the mirror. The locations may be copied from the primary to secondary storage volume to reconstruct the data mirror. The performance impact of the tracking component is minimal and a shared network resource is offered that increases fault tolerance in the event of backup device failures.

Abstract: Provided are a method, system, and article of manufacture, wherein a controller receives a request from one of a plurality of hosts. The controller determines whether a primary storage control unit coupled to the controller is operational. A response is generated by accessing the primary storage control unit, in response to determining that the primary storage control unit is operational. The response is generated by accessing a secondary storage control unit, in response to determining that the primary storage control unit is not operational, wherein data is replicated synchronously from the primary storage control unit to the secondary storage control unit.

Abstract: Disclosed are a system, a method, and a computer program product to provide for the optimization of the output transfer load balance between the peer computers transferring data to one or more storage devices. The peer computers receive, organize and transfer the data to storage devices. The data set is composed of a plurality of data transfers. After an initial division of the data transfers between the two peers, each peer will have assigned responsibility for a number of data transfers. If the one of the peer computers completes offloading transactions earlier than the other peer, then the peer that is still transferring data will employ the other peer to execute a portion of the remaining data transfers. The operation of the system is symmetrical in that either peer may assist the other peer depending upon which peer has idle time.

Abstract: Provided are a method, system, and article of manufacture wherein a command is received for writing data to a first storage location. A determination is made that previously written data is stored in the first storage location. The previously written data is copied to a second storage location, in response to determining that the previously written data is stored in the first storage location. The data is written to the first storage location, in response to copying the previously written data to the second storage location.

Abstract: Disclosed is a technique for data synchronization. A first identifier for a portion of data on a primary volume is determined, wherein a unique identifier is associated with each portion of data at the primary volume. A second identifier for a portion of corresponding data at a secondary volume is determined, wherein a unique identifier is associated with each portion of data at the secondary volume. The first and second identifiers are compared. When the first and second identifiers do not match, the portion of corresponding data at the secondary volume in a storage device is replaced with the portion of data at the primary volume.

Abstract: Provided are a method, system, and program for establishing copy relationships to copy source data to target data. A request is received to establish a copy relationship indicating to copy source data to target data. A determination is made as to whether the source data defined in the request comprises target data defined in a preexisting copy relationship. A determination is made as to whether base source data copied to the target data in the preexisting copy relationship also comprises the source data indicated in the request in response to determining that the source data defined in the request comprises target data in the preexisting copy relationship. A new copy relationship is defined to copy the determined base source data to the target data indicated in the request.

Abstract: An apparatus, system, and method are disclosed for initializing a synchronized remote database. A creation module creates a first backup table of a backup database from a schema for a primary table of a primary database. A read module reads each row from the primary table with an application server configured to manage access to the primary database by a database application. A construction module constructs a SQL command for each row of the primary table. Each SQL command inserts data of a primary table row in the first backup table. An application module applies each SQL command to the first backup table to mirror the primary table at the first backup table.

Abstract: An apparatus, system, and method are disclosed for efficient creation of point-in-time versions of data using differencing in a read-before-write environment. Included in an embodiment of the invention are a receive module that receives a data block sent from a primary data storage system, a read module that reads a data block from a secondary data storage device into random access memory, the data block corresponding to the data block sent from the primary data storage system, a comparison module that compares the data block sent from the primary data storage system to the data block from the secondary data storage device and creates a differencing data file, a compression module that compresses the differencing data file and to create a compressed differencing data file, and a differencing storage module stores the compressed differencing data file in a differencing storage device.

Abstract: A method is disclosed for reliably updating a data group in a read-before-write data replication environment. The method reliably updates the data group by receiving an updated data group sent from a first storage medium to a second storage medium, comparing the updated data group with a previous data group previously existing on the second storage medium and writing the updated data group to the second storage medium. The read-before-write and differencing method disclosed maintain reliability by storing multiple copies of changes made to the second storage medium during and after the write process.

Abstract: An apparatus, system, and method are disclosed for reliably updating a data group in a data replication environment. The apparatus, system, and method reliably update the data group by receiving an updated data group sent from a first storage medium to a second storage medium, comparing the updated data group with a previous data group previously existing on the second storage medium and writing the updated data group to the second storage medium. The read-before-write and differencing method disclosed maintain reliability by storing multiple copies of changes made to the second storage medium during and after the write process.

Abstract: A network component useful in tracking write activity by writing logs containing write address information is described. The tracking component may be used in networked systems employing data mirrors to record data block addresses written to a primary storage volume during the time a data mirror is unavailable. The tracking component can be available to any network originating node, and may therefore track write activity on multiple volumes. At the time a data mirror is reconstructed, the log written may be used to construct a list of block addresses pointing to locations on a primary storage volume wherein data differs from a secondary storage volume member of the mirror. The locations may be copied from the primary to secondary storage volume to reconstruct the data mirror. The performance impact of the tracking component is minimal and a shared network resource is offered that increases fault tolerance in the event of backup device failures.