Abstract: One or more techniques and/or systems are provided for mirror vote synchronization. For example, a first storage device is located at a first storage site, and a second storage device is located at a second storage site. The second storage device is configured according to a data mirroring configuration where data from the first storage device is mirrored to the second storage device. Mirror vote metadata is generated based upon an up-to-date state of the data mirroring configuration. The mirror vote metadata indicates whether the first storage device and/or the second storage device are up-to-date or not. The mirror vote metadata may be replicated between the first storage site and the second storage site. If the first storage site fails, then the second storage site may provide switchover operation using the second storage device based upon the mirror vote metadata.

Abstract: One or more techniques and/or systems are provided for mirror vote synchronization. For example, a first storage device is located at a first storage site, and a second storage device is located at a second storage site. The second storage device is configured according to a data mirroring configuration where data from the first storage device is mirrored to the second storage device. Mirror vote metadata is generated based upon an up-to-date state of the data mirroring configuration. The mirror vote metadata indicates whether the first storage device and/or the second storage device are up-to-date or not. The mirror vote metadata may be replicated between the first storage site and the second storage site. If the first storage site fails, then the second storage site may provide switchover operation using the second storage device based upon the mirror vote metadata.

Abstract: One or more techniques and/or systems are provided for mirror vote synchronization. For example, a first storage device is located at a first storage site, and a second storage device is located at a second storage site. The second storage device is configured according to a data mirroring configuration where data from the first storage device is mirrored to the second storage device. Mirror vote metadata is generated based upon an up-to-date state of the data mirroring configuration. The mirror vote metadata indicates whether the first storage device and/or the second storage device are up-to-date or not. The mirror vote metadata may be replicated between the first storage site and the second storage site. If the first storage site fails, then the second storage site may provide switchover operation using the second storage device based upon the mirror vote metadata.

Abstract: One or more techniques and/or systems are provided for mirror vote synchronization. For example, a first storage device is located at a first storage site, and a second storage device is located at a second storage site. The second storage device is configured according to a data mirroring configuration where data from the first storage device is mirrored to the second storage device. Mirror vote metadata is generated based upon an up-to-date state of the data mirroring configuration. The mirror vote metadata indicates whether the first storage device and/or the second storage device are up-to-date or not. The mirror vote metadata may be replicated between the first storage site and the second storage site. If the first storage site fails, then the second storage site may provide switchover operation using the second storage device based upon the mirror vote metadata.

Abstract: One or more techniques and/or systems are provided for mirror vote synchronization. For example, a first storage device is located at a first storage site, and a second storage device is located at a second storage site. The second storage device is configured according to a data mirroring configuration where data from the first storage device is mirrored to the second storage device. Mirror vote metadata is generated based upon an up-to-date state of the data mirroring configuration. The mirror vote metadata indicates whether the first storage device and/or the second storage device are up-to-date or not. The mirror vote metadata may be replicated between the first storage site and the second storage site. If the first storage site fails, then the second storage site may provide switchover operation using the second storage device based upon the mirror vote metadata.

Abstract: One or more techniques and/or systems are provided for mirror vote synchronization. For example, a first storage device is located at a first storage site, and a second storage device is located at a second storage site. The second storage device is configured according to a data mirroring configuration where data from the first storage device is mirrored to the second storage device. Mirror vote metadata is generated based upon an up-to-date state of the data mirroring configuration. The mirror vote metadata indicates whether the first storage device and/or the second storage device are up-to-date or not. The mirror vote metadata may be replicated between the first storage site and the second storage site. If the first storage site fails, then the second storage site may provide switchover operation using the second storage device based upon the mirror vote metadata.

Abstract: A method, system and computer program product for performing an expansion of a disk array. Upon the failure of a disk in the disk array, the failed disk may be rebuilt stripe by stripe in the spare units distributed among other disks in the disk array. Upon repairing or replacing the failed disk with a spare disk, the repaired or spare disk may be rebuilt stripe by stripe using the data from the spare units. Upon receiving a write request to a stripe unit that has been rebuilt in the repaired or spare disk during expansion, the data of the request may be written in the stripe unit requested. Further, the data written may be mirrored, i.e., copied and stored, in the spare unit corresponding to the stripe unit requested. By mirroring the data to the corresponding spare unit, tracking each stripe that was updated during expansion may be eliminated.

Abstract: A computer-implemented method for managing data snapshots among storage volumes to facilitate transitive, distributed snapshot operations such that a read request or write request can be made to any volume in a snapshot includes establishing respective snapshot tables for the volumes. Each table can correlate, for each chunk of data, a source volume and a target volume. In response to a read request for chunks in one the volumes, the respective snapshot table is accessed, and the read directed to the source volume indicated in the snapshot table. Likewise, in response to a write request for chunks in a storage volume, the table associated with the volume is accessed, and the write is directed to the target volume indicated in the table. For each chunk, the source volume is the same across all tables, such that a read or write involves no more than a single storage volume.

Abstract: A data processing system and method manage usage metadata nodes about data snapshots of data write operations among storage volumes of the system while conserving metadata nodes. Metadata sublogging is achieved by dividing metadata segments into subsegments and tracking them by use of a bitmap.

Abstract: A method, apparatus, and program product applicable within a multi-drive data storage system for adaptively allocating data reconstruction resources. In accordance with the method of the present invention, responsive to a detected drive failure, a resource allocation manager periodically determines the number of pending host system processing requests. The determined number of pending host system processing requests is then compared to a predetermined threshold value. Finally, a number of processing resources are allocated to data reconstruction in accordance with the results of the comparison of the number of pending host system processing requests to the predetermined threshold.

Abstract: A method, system and computer program product for performing an expansion of a disk array. Upon the failure of a disk in the disk array, the failed disk may be rebuilt stripe by stripe in the spare units distributed among other disks in the disk array. Upon repairing or replacing the failed disk with a spare disk, the repaired or spare disk may be rebuilt stripe by stripe using the data from the spare units. Upon receiving a write request to a stripe unit that has been rebuilt in the repaired or spare disk during expansion, the data of the request may be written in the stripe unit requested. Further, the data written may be mirrored, i.e., copied and stored, in the spare unit corresponding to the stripe unit requested. By mirroring the data to the corresponding spare unit, tracking each stripe that was updated during expansion may be eliminated.

Abstract: A method, apparatus, and program product applicable within a multi-drive data storage system for adaptively allocating data reconstruction resources. In accordance with the method of the present invention, responsive to a detected drive failure, a resource allocation manager periodically determines the number of pending host system processing requests. The determined number of pending host system processing requests is then compared to a predetermined threshold value. Finally, a number of processing resources are allocated to data reconstruction in accordance with the results of the comparison of the number of pending host system processing requests to the predetermined threshold.

Abstract: A data processing system and method manage usage metadata nodes about data snapshots of data write operations among storage volumes of the system while conserving metadata nodes. Metadata sublogging is achieved by dividing metadata segments into subsegments and tracking them by use of a bitmap.

Abstract: The present invention provides a method and system for more efficiently providing a copy of a portion of a source drive of a plurality of drives in a redundant array of inexpensive disks (RAID) data storage system. The portion of the source drive includes a plurality of segments. The method and system include providing the copy of the plurality of segments from the source drive to the target drive. The plurality of segments can be modified during the step of providing the copy. The method and system further include providing another copy of a portion of the plurality of segments that have been modified since the step of providing the copy commenced if a portion of the plurality of segments have been modified since copying commenced.

Abstract: A method and system for providing a backup of a portion of a source drive of a plurality of drives in a redundant array of inexpensive disks (RAID) data storage system is disclosed. The portion of the source includes a plurality of segments. The method and system include associating the source drive with a target drive of the plurality of drives and providing a copy of the plurality of segments on the target drive. The copy is provided such that input to and output from source drive and the target drive are allowed during the step of providing the copy of the plurality of segments.