Abstract: A distributed network of storage elements (DNSE) is provided in which the physical capacity of each drive is split into a set of equal sized logical splits which are individually protected within the DNSE using separate RAID groups. To reduce restoration latency, members of the RAID groups having a member in common on a given drive are spread within the DNSE to minimize the number of sets of drives within the DNSE that have RAID members in common. By causing the splits to be protected by RAID groups, restoration of the splits may occur in parallel involving multiple drives within the DNSE. By minimizing the overlap between RAID members on various drives, failure of a given drive will not require multiple reads from another drive in the DNSE. Likewise, spare splits are distributed to enable write recovery to be performed in parallel on multiple drives within the DNSE.

Abstract: A distributed network of storage elements (DNSE) is provided in which the physical capacity of each drive is split into a set of equal sized logical splits which are individually protected within the DNSE using separate RAID groups. To reduce restoration latency, members of the RAID groups having a member in common on a given drive are spread within the DNSE to minimize the number of sets of drives within the DNSE that have RAID members in common. By causing the splits to be protected by RAID groups, restoration of the splits may occur in parallel involving multiple drives within the DNSE. By minimizing the overlap between RAID members on various drives, failure of a given drive will not require multiple reads from another drive in the DNSE. Likewise, spare splits are distributed to enable write recovery to be performed in parallel on multiple drives within the DNSE.

Abstract: A distributed network of storage elements (DNSE) is provided in which the physical capacity of each drive is split into a set of equal sized logical splits which are individually protected within the DNSE using separate RAID groups. To reduce restoration latency, members of the RAID groups having a member in common on a given drive are spread within the DNSE to minimize the number of sets of drives within the DNSE that have RAID members in common. By causing the splits to be protected by RAID groups, restoration of the splits may occur in parallel involving multiple drives within the DNSE. By minimizing the overlap between RAID members on various drives, failure of a given drive will not require multiple reads from another drive in the DNSE. Likewise, spare splits are distributed to enable write recovery to be performed in parallel on multiple drives within the DNSE.

Abstract: Described are techniques for processing a request to update a globally shared data item. The request is received at a first processor designated as the master processor. Other processors are designated as non-master processors. The first processor sends a synchronization request message to the other processors. The first processor waits a predetermined amount of time for the other processors to signal to the first processor regarding commitment in executing the request. Responsive to the first processor receiving the signal from the other processors first processing is performed that includes the first processor notifying the other processors regarding completion of a first synchronization point, updating the globally shared data item by said first processor, and waiting, by the other processors, for notification from the first processor regarding completion of a second synchronization point thereby indicating that updating of the globally shared data item is completed.

Abstract: Described are techniques for performing data migration for a source logical volume and a target. The target is configured as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target, and if the target is configured storage of another logical volume of the data storage system, the configured storage is remapped as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target. One or more invalid bits are set indicating that the target does not contain a valid copy of data from the source logical volume. Data is copied from the first mirror of the source logical volume to the target. Invalid bits are cleared as data portions of the first mirror of the source logical volume are copied to the target.

Abstract: Described are techniques for performing data migration for a source logical volume and a target. The target is configured as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target, and if the target is configured storage of another logical volume of the data storage system, the configured storage is remapped as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target. One or more invalid bits are set indicating that the target does not contain a valid copy of data from the source logical volume. Data is copied from the first mirror of the source logical volume to the target. Invalid bits are cleared as data portions of the first mirror of the source logical volume are copied to the target.