Abstract: A method for more effectively distributing the I/O workload in a data replication system is disclosed herein. In selected embodiments, such a method may include generating an I/O request and identifying a storage resource group associated with the I/O request. In the event the I/O request is associated with a first storage resource group, the I/O request may be directed to a first storage device and a copy of the I/O request may be mirrored from the first storage device to a second storage device. Alternatively, in the event the I/O request is associated with a second storage resource group, the I/O request may be directed to a second storage device and a copy of the I/O request may be mirrored from the second storage device to the first storage device.

Abstract: A method for migrating extents between extent pools in a tiered storage architecture maintains a data access profile for an extent over a period of time. Using the data access profile, the method generates an extent profile graph that predicts data access rates for the extent into the future. The slope of the extent profile graph is calculated and used to determine whether the extent will reach a migration threshold within a specified “look-ahead” time. If so, the method calculates a migration window that allows the extent to be migrated prior to reaching the migration threshold. In certain embodiments, the method determines the overall performance impact on the source extent pool and destination extent pool during the migration window. If the overall performance impact is below a designated impact threshold, the method migrates the extent during the migration window.

Abstract: A method for managing extents in a data storage system includes monitoring usage statistics for an extent residing on one or more powered-up storage devices. In the event the extent has not been accessed for specified period of time (as determined from the usage statistics), the method automatically compresses the extent and migrates the extent to an intermediate repository. Once the amount of data in the intermediate repository reaches a specified level, the method migrates the extent from the intermediate repository to one or more normally powered-down storage devices. If I/O is received for the extent while it resides in the normally powered-down storage devices or the intermediate repository, the method automatically migrates the extent from the normally powered-down storage devices or the intermediate repository to the normally powered-up storage devices. A corresponding apparatus and computer program product are also disclosed.

Abstract: A method for migrating extents between extent pools in a tiered storage architecture maintains a data access profile for an extent over a period of time. Using the data access profile, the method generates an extent profile graph that predicts data access rates for the extent into the future. The slope of the extent profile graph is calculated and used to determine whether the extent will reach a migration threshold within a specified “look-ahead” time. If so, the method calculates a migration window that allows the extent to be migrated prior to reaching the migration threshold. In certain embodiments, the method determines the overall performance impact on the source extent pool and destination extent pool during the migration window. If the overall performance impact is below a designated impact threshold, the method migrates the extent during the migration window. A corresponding apparatus and computer program product are also disclosed herein.

Abstract: A method for more effectively distributing the I/O workload in a data replication system is disclosed herein. In selected embodiments, such a method may include generating an I/O request and identifying a storage resource group associated with the I/O request. In the event the I/O request is associated with a first storage resource group, the I/O request may be directed to a first storage device and a copy of the I/O request may be mirrored from the first storage device to a second storage device. Alternatively, in the event the I/O request is associated with a second storage resource group, the I/O request may be directed to a second storage device and a copy of the I/O request may be mirrored from the second storage device to the first storage device.

Abstract: Provided are a method, system, and computer program product for using a migration cache to cache tracks during migration. In response to a migration operation, a determination is made of a first set of tracks in the source storage indicated in an extent list and of a second set of tracks in the extent. The tracks in the source storage in the first set are copied to a migration cache. The tracks in the second set are copied directly from the source storage to the destination storage without buffering in the migration cache. The tracks in the first set are copied from the migration cache to the destination storage. The migration operation is completed in response to copying the first set of tracks from the migration cache to the destination storage and copying the second set of tracks from the source storage to the destination storage.

Abstract: A method for managing extents in a data storage system includes monitoring usage statistics for an extent residing on one or more powered-up storage devices. In the event the extent has not been accessed for specified period of time (as determined from the usage statistics), the method automatically compresses the extent and migrates the extent to an intermediate repository. Once the amount of data in the intermediate repository reaches a specified level, the method migrates the extent from the intermediate repository to one or more normally powered-down storage devices. If I/O is received for the extent while it resides in the normally powered-down storage devices or the intermediate repository, the method automatically migrates the extent from the normally powered-down storage devices or the intermediate repository to the normally powered-up storage devices. A corresponding apparatus and computer program product are also disclosed.

Abstract: A method for more effectively distributing the I/O workload in a data replication system is disclosed herein. In selected embodiments, such a method may include generating an I/O request and identifying a storage resource group associated with the I/O request. In the event the I/O request is associated with a first storage resource group, the I/O request may be directed to a first storage device and a copy of the I/O request may be mirrored from the first storage device to a second storage device. Alternatively, in the event the I/O request is associated with a second storage resource group, the I/O request may be directed to a second storage device and a copy of the I/O request may be mirrored from the second storage device to the first storage device. A corresponding system, apparatus, and computer program product are also disclosed and claimed herein.

Abstract: Provided are a method, system, and computer program product for using a migration cache to cache tracks during migration. In response to a migration operation, a determination is made of a first set of tracks in the source storage indicated in an extent list and of a second set of tracks in the extent. The tracks in the source storage in the first set are copied to a migration cache. The tracks in the second set are copied directly from the source storage to the destination storage without buffering in the migration cache. The tracks in the first set are copied from the migration cache to the destination storage. The migration operation is completed in response to copying the first set of tracks from the migration cache to the destination storage and copying the second set of tracks from the source storage to the destination storage.

Abstract: Provided are a method, system, and computer program product for using a migration cache to cache tracks during migration. Indication is made in an extent list of tracks in an extent in a source storage subject to Input/Output (I/O) requests. A migration operation is initiated to migrate the extent from the source storage to a destination storage. In response to initiating the migration operation, a determination is made of a first set of tracks in the extent in the source storage indicated in the extent list. A determination is also made of a second set of tracks in the extent. The tracks in the source storage in the first set are copied to a migration cache, wherein updates to the tracks in the migration cache during the migration operation are applied to the migration cache. The tracks in the second set are copied directly from the source storage to the destination storage without buffering in the migration cache. The tracks in the first set are copied from the migration cache to the destination storage.

Abstract: A method, system, and computer program product for determining severity of communication deficiencies and isolating faults in a power network of a data processing environment is provided. Pursuant to a continuous graph theory analysis, each of a plurality of nodes of the power network is initialized with the same arbitrary value. Each of a plurality of network paths connecting each of the plurality of nodes is analyzed. Upon a successful communication or communication deficiency over one of the plurality of network paths, one arbitrary value of one of the plurality of nodes connected to the one of the plurality of network paths is incremented or decremented, respectively by a weighting value. The incrementing and decrementing is repeated until a threshold is reached and a recovery is performed on which of the plurality of nodes has a lower adjusted value.

Abstract: Provided are a method, system, and article of manufacture for synchronizing device error information among nodes. A first node performs an action with respect to a first node error counter for a device in communication with the first node and a second node. The first node transmits a message to the second node indicating the device and the action performed with respect to the first node error counter for the device. The second node performs the action indicated in the message with respect to a second node error counter for the device indicated in the message, wherein the second node error counter corresponds to the first node error counter for the device.

Abstract: A method, system, and computer program product for determining severity of communication deficiencies and isolating faults in a power network of a data processing environment is provided. Pursuant to a continuous graph theory analysis, each of a plurality of nodes of the power network is initialized with the same arbitrary value. Each of a plurality of network paths connecting each of the plurality of nodes is analyzed. Upon a successful communication or communication deficiency over one of the plurality of network paths, one arbitrary value of one of the plurality of nodes connected to the one of the plurality of network paths is incremented or decremented, respectively by a weighting value. The incrementing and decrementing is repeated until a threshold is reached and a recovery is performed on which of the plurality of nodes has a lower adjusted value.

Abstract: Provided are a method, system, and article of manufacture for synchronizing device error information among nodes. A first node performs an action with respect to a first node error counter for a device in communication with the first node and a second node. The first node transmits a message to the second node indicating the device and the action performed with respect to the first node error counter for the device. The second node performs the action indicated in the message with respect to a second node error counter for the device indicated in the message, wherein the second node error counter corresponds to the first node error counter for the device.

Abstract: Provided are a method, system and program for processing complexes to access shared devices. A lock to a plurality of shared devices is maintained and accessible to a first and second processing systems. The first processing complex determines a first delay time and the second processing complex determines a second delay time. The first processing complex issues a request for the lock in response to expiration of the first delay time and the second processing complex issues a request for the lock in response to expiration of the second delay time.