Reducing overlap through shuffle and keeping relationship balance on mapped RAID system and method

Patent metadata

Field	Value
Publication number	US-10782894-B1
Application number	US-201715664790-A
Country	US
Kind code	B1
Filing date	Jul 31, 2017
Priority date	Jul 31, 2017
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

A method, computer program product, and computer system for reducing, by a computing device, overlap in a RAID extent group by moving a first disk extent in an extent pool from a source disk to a target disk in a Mapped RAID group. A neighborhood matrix for the Mapped RAID group may be balanced by moving a second disk extent in the extent pool from the source disk to the target disk in the Mapped RAID group.

First claim

What is claimed is:

1. A computer-implemented method comprising:
identifying, via a computing device, overlap in a sub RAID extent group, wherein the sub RAID extent group includes at least a first RAID extent group and a second RAID extent group, wherein the overlap occurs when the first RAID extent group and the second RAID extent group both include one or more disk extents from a same disk;
reducing overlap in the sub RAID extent group by moving a first disk extent in an extent pool from a source disk to a target disk in a Mapped RAID group, wherein reducing overlap in the sub RAID extent group results in the first RAID extent group and the second RAID extent group not sharing any disk extents in common;
checking if each disk in a disk list in the extent pool has been checked; and
balancing a neighborhood matrix for the Mapped RAID group by moving a second disk extent in the extent pool from the source disk to the target disk in the Mapped RAID group, wherein the neighborhood matrix indicates how many times a disk extent from a respective disk is combined with a disk extent from another disk in a RAID extent.

2. The computer-implemented method of claim 1 wherein reducing overlap in the sub RAID extent group includes sorting the disk list in the extent pool by free disk extent count.

3. The computer-implemented method of claim 1 further comprising updating the neighborhood matrix after at least one of moving the first disk extent from the source disk to the target disk and moving the second disk extent from the source disk to the target disk.

4. The computer-implemented method of claim 1 wherein reducing overlap in the sub RAID extent group includes determining that a score for moving the first disk extent from the source disk to the target disk is valid.

5. The computer-implemented method of claim 4 wherein the target disk results in the score for moving the first disk extent being a maximum score in the neighborhood matrix for moving the first disk extent from the source disk to the target disk.

6. The computer-implemented method of claim 1 wherein balancing the neighborhood matrix includes determining that a score for moving the second disk extent from the source disk to the target disk is valid.

7. The computer-implemented method of claim 6 wherein the target disk results in the score for moving the second disk extent being a maximum score in the neighborhood matrix for moving the second disk extent from the source disk to the target disk.

8. A computer program product residing on a non-transitory computer readable storage medium having a plurality of instructions stored thereon which, when executed across one or more processors, causes at least a portion of the one or more processors to perform operations comprising:
identifying, via a computing device, overlap in a sub RAID extent group, wherein the sub RAID extent group includes at least a first RAID extent group and a second RAID extent group, wherein the overlap occurs when the first RAID extent group and the second RAID extent group both include one or more disk extents from a same disk;
reducing overlap in the sub RAID extent group by moving a first disk extent in an extent pool from a source disk to a target disk in a Mapped RAID group, wherein reducing overlap in the sub RAID extent group results in the first RAID extent group and the second RAID extent group not sharing any disk extents in common;
checking if each disk in a disk list in the extent pool has been checked; and
balancing a neighborhood matrix for the Mapped RAID group by moving a second disk extent in the extent pool from the source disk to the target disk in the Mapped RAID group, wherein the neighborhood matrix indicates how many times a disk extent from a respective disk is combined with a disk extent from another disk in a RAID extent.

9. The computer program product of claim 8 wherein reducing overlap in the sub RAID extent group includes sorting the disk list in the extent pool by free disk extent count.

10. The computer program product of claim 8 wherein the operations further comprise updating the neighborhood matrix after at least one of moving the first disk extent from the source disk to the target disk and moving the second disk extent from the source disk to the target disk.

11. The computer program product of claim 8 wherein reducing overlap in the sub RAID extent group includes determining that a score for moving the first disk extent from the source disk to the target disk is valid.

12. The computer program product of claim 11 wherein the target disk results in the score for moving the first disk extent being a maximum score in the neighborhood matrix for moving the first disk extent from the source disk to the target disk.

13. The computer program product of claim 8 wherein balancing the neighborhood matrix includes determining that a score for moving the second disk extent from the source disk to the target disk is valid.

14. The computer program product of claim 13 wherein the target disk results in the score for moving the second disk extent being a maximum score in the neighborhood matrix for moving the second disk extent from the source disk to the target disk.

15. A computing system including one or more processors and one or more memories configured to perform operations comprising:
identifying, via a computing device, overlap in a sub RAID extent group, wherein the sub RAID extent group includes at least a first RAID extent group and a second RAID extent group, wherein the overlap occurs when the first RAID extent group and the second RAID extent group both include one or more disk extents from a same disk;
reducing overlap in the sub RAID extent group by moving a first disk extent in an extent pool from a source disk to a target disk in a Mapped RAID group, wherein reducing overlap in the sub RAID extent group results in the first RAID extent group and the second RAID extent group not sharing any disk extents in common;
checking if each disk in a disk list in the extent pool has been checked; and
balancing a neighborhood matrix for the Mapped RAID group by moving a second disk extent in the extent pool from the source disk to the target disk in the Mapped RAID group, wherein the neighborhood matrix indicates how many times a disk extent from a respective disk is combined with a disk extent from another disk in a RAID extent.

16. The computing system of claim 15 wherein reducing overlap in the sub RAID extent group includes sorting the disk list in the extent pool by free disk extent count.

17. The computing system of claim 15 wherein reducing overlap in the sub RAID extent group includes determining that a score for moving the first disk extent from the source disk to the target disk is valid.

18. The computing system of claim 17 wherein the target disk results in the score for moving the first disk extent being a maximum score in the neighborhood matrix for moving the first disk extent from the source disk to the target disk.

19. The computing system of claim 15 wherein balancing the neighborhood matrix includes determining that a score for moving the second disk extent from the source disk to the target disk is valid.

20. The computing system of claim 19 wherein the target disk results in the score for moving the second disk extent being a maximum score in the neighborhood matrix for moving the second disk extent from the source disk to the target disk.

Assignees

• Emc Ip Holding Co Llc

Inventors

• Han Geng
• Usvyatsky Ilya
• Gao Jian
• Dong Jibing
• Kang Jamin
• Gao Hongpo

Classifications

• G06F11/1092

  Rebuilding, e.g. when physically replacing a failing disk · CPC title

• G06F3/0689 Primary

  Disk arrays, e.g. RAID, JBOD · CPC title

• G06F3/0614

  Improving the reliability of storage systems · CPC title

• G06F3/061

  Improving I/O performance · CPC title

• G06F3/0647

  Migration mechanisms · CPC title