Performing discard commands on RAID storage devices

• US 9,588,693 B2
• Filed: 04/06/2015
• Issued: 03/07/2017
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Original Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Inventors: Patoka, Mikul, Snitzer, Michael A.
• Primary Examiner(s): TSUI, DANIEL D
• Application Number:
  US14/679,376
• Publication Number:
  US 20150227317A1
• Time in Patent Office: 701 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0238 Memory management in non-volatile memory, e.g. resistive RAM or ferroelectric memory
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

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.

Claims

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 of the plurality of storage devices partitioned into a plurality of partitions to store a respective plurality of physical sectors;

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;

identifying, in view of the first physical sector number and the second physical sector number, a range of physical sectors that includes all physical sectors of one or more parity groups; and

issuing, by the processing device, a command to the plurality of storage devices to free the range of physical sectors.

2. The method of claim 1, wherein the RAID comprises solid state devices (SSDs).

3. The method of claim 1, wherein the storage devices are organized as RAID-0, RAID-4, RAID-5 or RAID-6.

4. The method of claim 1, wherein identifying the first physical sector number on a current storage device comprises:

adding, to the first logical sector number modulo a partition size, a product of the partition size and an integer quotient of the first logical sector number and a number of storage devices.

5. The method of claim 4, further comprising:

rounding down the physical sector number incremented by one to a partition boundary responsive to determining that an integer quotient of the first logical sector number and a partition size modulo a number of storage devices does not exceed an ordinal number of the current storage device.

6. The method of claim 4, further comprising:

rounding down the physical sector number to a partition boundary responsive to determining that an integer quotient of the first logical sector number and a partition size modulo a number of storage devices exceeds an ordinal number of the current storage device.

7. The method of claim 6, wherein rounding down the physical sector number comprises applying a bit mask.

8. A system comprising:

a plurality of storage devices organized as a Redundant Array of Independent Disks (RAID), each storage device of the plurality of storage devices partitioned into a plurality of partitions to store a respective plurality of physical sectors; and

a processing device operatively coupled to the plurality of storage devices, the processing device to;

receive a request to free a range of logical sectors that is mapped to the plurality of storage devices, each storage device partitioned into a plurality of partitions to store a plurality of physical sectors;

identify 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;

identify 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;

identify, in view of the first physical sector number and the second physical sector number, a range of physical sectors that includes all physical sectors of one or more parity groups; and

issue a command to the plurality of storage devices to free the range of physical.

9. The system of claim 8, wherein the RAID comprises solid state devices (SSDs).

10. The system of claim 8, wherein the storage devices are organized as RAID-0, RAID-4, RAID-5 or RAID-6.

11. The system of claim 8, wherein to identify the first physical sector number on a current storage device, the processing device is to:

add, to the first logical sector number modulo a partition size, a product of the partition size and an integer quotient of the first logical sector number and a number of storage devices.

12. The system of claim 11, wherein the processing device is further to:

round down the physical sector number incremented by one to a partition boundary responsive to determining that an integer quotient of the first logical sector number and a partition size modulo a number of storage devices does not exceed an ordinal number of the current storage device.

13. The system of claim 11, wherein the processing device is further to:

round down the physical sector number to a partition boundary responsive to determining that an integer quotient of the first logical sector number and a partition size modulo a number of storage devices exceeds an ordinal number of the current storage device.

14. The system of claim 13, wherein to round down the physical sector number, the processing device is to:

apply a bit mask.

15. A computer readable non-transitory storage medium comprising instructions to cause a processing device to:

receive, by the 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 of the plurality of storage devices partitioned into a plurality of partitions to store a respective plurality of physical sectors;

identify 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;

identify 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;

identify, in view of the first physical sector number and the second physical sector number, a range of physical sectors that includes all physical sectors of one or more parity groups; and

issue, by the processing device, a command to the plurality of storage devices to free the range of physical sectors.

16. The computer readable non-transitory storage medium of claim 15, wherein the RAID comprises solid state devices (SSDs).

17. The computer readable non-transitory storage medium of claim 15, wherein the storage devices are organized as RAID-0, RAID-4, RAID-5 or RAID-6.

18. The computer readable non-transitory storage medium of claim 15, wherein executable instructions to identify the first physical sector number on a current storage device comprise executable instructions to cause the processing device to:

add, to the first logical sector number modulo a partition size, a product of the partition size and an integer quotient of the first logical sector number and a number of storage devices.

19. The computer readable non-transitory storage medium of claim 18, further comprising executable instructions to cause the processing device to:

round down the physical sector number incremented by one to a partition boundary responsive to determining that an integer quotient of the first logical sector number and a partition size modulo a number of storage devices does not exceed an ordinal number of the current storage device.

20. The computer readable non-transitory storage medium of claim 18, further comprising executable instructions to cause the processing device to:

round down the physical sector number to a partition boundary responsive to determining that an integer quotient of the first logical sector number and a partition size modulo a number of storage devices exceeds an ordinal number of the current storage device.