Systems and methods for storing parity groups

• US 7,917,695 B2
• Filed: 02/08/2008
• Issued: 03/29/2011
• Est. Priority Date: 01/29/2001
• Status: Expired due to Fees

• Current Assignee: Overland Storage Incorporated (Silicon Valley Technology Partners LLC)
• Original Assignee: Overland Storage Incorporated (Silicon Valley Technology Partners LLC)
• Inventors: Schweitzer, James R., Bolstad, Gregory D., Staub, John R., Randall, Jay G., Priester, Wilbur George, Ulrich, Thomas R.
• Primary Examiner(s): Bragdon; Reginald G
• Assistant Examiner(s): Faal; Baboucarr
• Application Number:
  US12/028,662
• Publication Number:
  US 20080126704A1
• Time in Patent Office: 1,145 Days
• Field of Search: None
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 2211/1004 Adaptive RAID, i.e. RAID system adapts to changing circumstances, e.g. RAID1 becomes RAID5 as disks fill up
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A system and method for dynamic redistribution of parity groups is described. The system and method for dynamic redistribution of parity groups operates on a computer storage system that includes a plurality of disk drives for storing parity groups. Each parity group includes storage blocks. The storage blocks include one or more data blocks and a parity block that is associated with the data blocks. Each of the storage blocks is stored on a separate disk drive such that no two storage blocks from a given parity set reside on the same disk drive. The computer system further includes a redistribution module to dynamically redistribute parity groups by combining some parity groups to improve storage efficiency.

Claims

1. A method for storing data in a computer network, the method comprising:

storing a first parity group comprising first data blocks and a first parity block, wherein said act of storing the first parity group comprises storing each of said first data blocks on a separate disk drive such that no two of the first data blocks reside on the same disk drive;

storing a second parity group comprising second data blocks and a second parity block, wherein said act of storing the second parity group comprises storing each of said second data blocks on a separate disk drive such that no two of the second data blocks reside on the same disk drive; and

redistributing said first parity group and said second parity group to improve storage efficiency.

2. The method of claim 1, further comprising storing metadata to describe a disk and logical block location of each of said first data blocks and said first parity block.

3. The method of claim 1, wherein said act of redistributing comprises combining the first parity group having a first size and the second parity group having a second size to produce a combined parity group having a third size, wherein said third size specifies a number of blocks that is, at most, one less than the number of disk drives available to store data from said combined parity group.

4. The method of claim 3, wherein the first size of the first parity group is larger than the second size of the second parity group.

5. The method of claim 1, wherein said act of redistributing comprises splitting the first parity group into a third parity group and a fourth parity group.

6. The method of claim 1, further comprising allocating a new parity group from a pool of available parity groups.

7. The method of claim 1, further comprising storing metadata that specifies at least one Gnid-string.

8. The method of claim 7, wherein said Gnid-string comprises a collection of gnids.

9. The method of claim 8, wherein each of said gnids comprises information for locating a specified gnode.

10. The method of claim 9, wherein the information for locating the specified gnode comprises a pointer to the specified gnode.

11. The method of claim 9, wherein the specified gnode comprises file attributes for a file corresponding to the gnode.

12. The method of claim 11, wherein the file attributes comprise at least one of a file id, a file access time, a file creation time and a file modification time.

13. A computer storage system comprising:

a first parity group comprising first data blocks and a first parity block;

a second parity group comprising second data blocks and a second parity block;

a plurality of disk drives for storing the first and second parity groups, each of the first data blocks of the first parity group being stored on a separate disk drive such that no two of the first data blocks reside on the same disk drive, and each of the second data blocks of the second parity group being stored on a separate disk drive such that no two of the second data blocks reside on the same disk drive; and

a redistribution module configured to redistribute the first parity group and the second parity group to improve storage efficiency.

14. The computer storage system of claim 13, further comprising metadata to describe a disk and logical block location of each of the first data blocks and the first parity block.

15. The computer storage system of claim 13, wherein the redistribution module is configured to redistribute at least one of the first parity group and the second parity group based on performance information of the plurality of disk drives.

16. The computer storage system of claim 13, wherein the redistribution module is configured to split the first parity group into a third parity group and a fourth parity group.

17. The computer storage system of claim 13, wherein the plurality of disk drives comprises Fibre Channel drives.

18. A system for storing data in a computer network, the system comprising:

first means for storing a first parity group comprising first data blocks and a first parity block by storing each of said first data blocks on a separate disk drive such that no two of the first data blocks reside on the same disk drive;

means for storing a second parity group comprising second data blocks and a second parity block by storing each of said second data blocks on a separate disk drive such that no two of the second data blocks reside on the same disk drive; and

means for redistributing said first parity group and said second parity group to improve storage efficiency.

19. The system of claim 18, wherein said distributing means comprises means for combining the first parity group having a first size and the second parity group having a second size to produce a combined parity group having a third size, wherein said third size specifies a number of blocks that is, at most, one less than the number of disk drives available to store data from said combined parity group.

20. The system of claim 18, wherein said distributing means comprises means for splitting the first parity group into a third parity group and a fourth parity group.