Performing discard commands on RAID storage devices

摘要

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.

主权项

1. A method comprising:
receiving, by a processing device, a request to free a range of logical sectors that is mapped to a plurality of storage devices organized as Redundant Array of Independent Disks (RAID), each storage device partitioned into a plurality of partitions to store a plurality of physical sectors; for each storage device, 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; 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; and issuing a command to free a range of physical sectors identified by the first physical sector number and the second physical sector number; wherein identifying a physical sector number on a current device comprises determining a first integer corresponding to a specified logical sector number and a second integer corresponding to the specified logical sector number, rounding down the first integer to a partition boundary responsive to determining that the second integer exceeds an ordinal number of the current device, and rounding down the first integer incremented by one to a partition boundary responsive to determining that the second integer does not exceed an ordinal number of the current device.