Abstract: A read request, a write request, and copy descriptor are constructed and sent to logical volumes of a device stack to complete a copy-offload operation between a source logical volume and a destination logical volume. The read request is forwarded to a source physical volume of a device stack and a write request is forwarded to a destination physical volume of the device stack. Responsive to detecting that the read request has been received by the source physical volume of the device stack and the write request has been received by a destination physical volume of the device stack, the driver of the source physical volume or the driver of the destination physical volume construct a copy-offload request to be sent to a storage device, the copy-offload request comprising the read request, the write request, and the copy descriptor. The copy-offload request is subsequently sent to the storage device.

Abstract: An example method for performing discard commands on Redundant Array of Independent Disks (RAID) devices may comprise receiving a request to free a range of logical sectors that is mapped to a plurality of storage devices organized as RAID. The method may further comprise identifying a first physical sector number corresponding to a first logical sector having a lowest number greater or equal than a starting logical sector number of the range of logical sectors. The method may further comprise identifying a second physical sector number corresponding to a second logical sector having a lowest number greater or equal than an ending logical sector number of the range of logical sectors. The method may further comprise issuing a single command to all of the plurality of storage devices to free a range of sectors identified by the first physical sector number and the second physical sector number.

Abstract: A method and system for efficiently freeing storage in a Redundant Array of Independent Disks (RAID) system. A computer system is coupled to storage devices that are organized as a RAID with block-level striping. Each storage device is partitioned into multiple physical sectors. The computer system receives a request to free a contiguous range of logical sectors that are mapped to the storage devices. In response, the computer system issues, for each storage device, a discard command to free contiguous physical sectors in the storage device that correspond to non-contiguous logical sectors.