Method and system for leveraging spares in a data storage system including a plurality of disk drives

• US 6,845,465 B2
• Filed: 09/17/2001
• Issued: 01/18/2005
• Est. Priority Date: 09/17/2001
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Hashemi, Ebrahim
• Primary Examiner(s): Beausoliel, Robert
• Assistant Examiner(s): PUENTE, EMERSON C
• Application Number:
  US09/955,527
• Publication Number:
  US 20030056142A1
• Time in Patent Office: 1,219 Days
• Field of Search: 714/6, 714/7, 714/8, 714/42, 711/112, 711/114
• US Class Current: 714/6.21
• CPC Class Codes: G06F 11/1084 Degraded mode, e.g. caused by single or multiple storage removals or disk failures
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• 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

Abstract

A method and apparatus for leveraging spare disks in a data storage system. Specifically the present invention describes a method for data recovery and redundancy in a data storage system having a plurality of disk drives. The data storage system is grouped into a plurality of arrays having data redundancy. The plurality of arrays is arranged in an optimum combination of arrays of mirrored pairs of disk drives, arrays of three disk drives in a redundant array of independent disks (RAID) configuration, and arrays of more than three disk drives in a RAID configuration to maximize performance while providing data redundancy. For every failure of one of said plurality of arrays due to a failed disk drive, a new array having data redundancy in a RAID configuration is dynamically created in said plurality of arrays. The new array is optimized for best performance and contains information from the failed disk drive.

Claims

1. A method for data redundancy in a data storage system, comprising:

a) grouping a plurality of disk drives into a plurality of arrays having data redundancy to optimize performance, and

b) for every failure of one of said plurality of arrays due to a failed disk drive, dynamically creating a new array having data redundancy in said plurality of arrays and that is optimized for performance, said new array containing information from said failed disk drive;

wherein b) comprises;

b1) upon failure of a first array in said plurality of arrays due to said first failed disk drive, dynamically choosing a second array in said plurality of arrays that has the smallest number of disk drives as between the remaining arrays, said second array having redundancy;

b2) combining disk drives from said first array, excluding said first failed disk drive, with disk drives from said second array to dynamically form said new array in a RAID configuration having data redundancy in said plurality of arrays; and

configuring said new array in a RAID-4 configuration.

2. A method for data redundancy in a data storage system, comprising:

a) grouping a plurality of disk drives into a plurality of arrays having data redundancy to optimize performance, and

b) for every failure of one of said plurality of arrays due to a failed disk drive, dynamically creating a new array having data redundancy in said plurality of arrays and that is optimized for performance, said new array containing information from said failed disk drive;

wherein b) comprises;

b1) upon failure of a first array in said plurality of arrays due to said first failed disk drive, dynamically choosing a second array in said plurality of arrays that has the smallest number of disk drives as between the remaining arrays, said second array having redundancy;

b2) combining disk drives from said first array, excluding said first failed disk drive, with disk drives from said second array to dynamically form said new array in a RAID configuration having data redundancy in said plurality of arrays; and

configuring said new array in a RAID 5 configuration.

3. A method for data redundancy in a data storage system, comprising:

a) grouping a plurality of disk drives into a plurality of arrays having data redundancy to optimize performance, including a first and second array;

b) upon failure of said first array due to a first failed disk drive, dynamically combining disk drives from said first array, excluding said first failed disk drive, with disk drives from said second array to form a first new array having data redundancy in said plurality of arrays;

wherein b) comprises

b1) if a first mirrored pair is available, choosing said first mirrored pair to be said second array;

b2) if no arrays of mirrored pairs of disk drives are present in said plurality of arrays, choosing an array having redundancy that has the next smallest number of disk drives to be said second array; and

b3) combining disk drives from said first array with disk drives from said second array to form said first new array in a RAID configuration having data redundancy in said plurality of arrays.

4. A method for data redundancy in a data storage system, comprising:

a) grouping a plurality of disk drives into a plurality of arrays having data redundancy to optimize performance, including a first and second array;

b) upon failure of said first array due to a first failed disk drive, dynamically combining disk drives from said first array, excluding said first failed disk drive, with disk drives from said second array to form a first new array having data redundancy in said plurality of arrays;

c) upon failure of said first new array due to a second failed disk drive, if a first minored pair is available, choosing said mirrored pair to be a third array in said plurality of arrays;

d) if no arrays of mirrored pairs of disk drives are present, choosing an array having redundancy that has the smallest number of disk drives to be said third array; and

e) upon failure of said first new array, combining disk drives from said first new array, not including said second failed disk drive, with disk drives from said third array, to form a second new array in a RAID configuration having data redundancy in said plurality of arrays.

5. The method for data redundancy as described in claim 4, further comprising:

f) upon failure of said second new array due to a third failed disk drive, if a second minored pair is available, choosing said second mirrored pair to be a fourth array in said plurality of arrays;

g) if no arrays of mirrored pairs of disk drives are present, choosing an array having redundancy that has the smallest number of disk drives to be said fourth array; and

h) combining disk drives from said second new array, not including said third failed disk drive, with disk drives from said fourth array, to form a third new array in a RAID configuration having data redundancy in said plurality of arrays.

6. A method for data redundancy in a data storage system, comprising:

a) grouping a plurality of disk drives into a plurality of arrays having data redundancy to optimize performance, including a first and second array;

b) upon failure of said first array due to a first failed disk drive, dynamically combining disk drives from said first array, excluding said first failed disk drive, with disk drives from said second array to form a first new array having data redundancy in said plurality of arrays;

c) upon failure of a third array due to a second failed disk drive, if a first mirrored pair is available, choosing said first mirrored pair to be a fourth array in said plurality of arrays;

d) if no arrays or mirrored pairs of disk drives are present, choosing an array having redundancy that has the smallest number of disk drives to be said fourth array; and

e) dynamically combining disk drives from said third array, not including said second failed disk drive, with disk drives from said fourth array to form a second new array in a RAID configuration having data redundancy in said plurality of arrays.

7. A data storage system comprising:

a plurality of disk drives comprising spare disks; and

an array controller comprising a processor, and a memory wherein said memory contains instructions that when executed implement a method comprising;

a) grouping a plurality of disk drives into a plurality of arrays having data redundancy to optimize performance, and

b) for every failure of one of said plurality of arrays due to a failed disk drive, dynamically creating a new array having data redundancy in said plurality of arrays and that is optimized for performance, said new array containing information from said failed disk drive;

wherein b) comprises;

b1 upon failure of a first array in said plurality of arrays due to said first failed disk drive, dynamically choosing a second array in said plurality of arrays that has the smallest number of disk drives as between the remaining arrays, said second array having redundancy;

b2) combining disk drives from said first array, excluding said first failed disk drive, with disk drives from said second array to dynamically form said new array in a RAID configuration having data redundancy in said plurality of arrays; and

configuring said new array in a RAID-4 configuration.

8. A data storage system, comprising:

a plurality of disk drives comprising spare disks; and

an array controller comprising a processor, and a memory wherein said memory contains instructions that when executed implement a method comprising;

a) grouping a plurality of disk drives into a plurality of arrays having data redundancy to optimize performance, and

b) for every failure of one of said plurality of arrays due to a failed disk drive, dynamically creating a new array having data redundancy in said plurality of arrays and that is optimized for performance, said new array containing information from said failed disk drive;

wherein b) comprises;

b1) upon failure of a first array in said plurality of arrays due to said first failed disk drive, dynamically choosing a second array in said plurality of arrays that has the smallest number of disk drives as between the remaining arrays, said second array having redundancy;

b2) combining disk drives from said first array, excluding said first failed disk drive, with disk drives from said second array to dynamically form said new array in a RAID configuration having data redundancy in said plurality of arrays; and

configuring said new array in a RAID-5 configuration.

9. A method, comprising:

grouping a plurality of disk drives into a plurality of arrays, each comprising a plurality of disk drives, and each array providing data redundancy within the respective array;

detecting a failure of a disk drive in one array of the plurality of arrays; and

in response to said detecting a failure, combining said one array with another array of the plurality of arrays into a new array comprising all non-failed disk drives of the two combined arrays.

10. The method of claim 9, wherein said another array comprises the smallest number of disk drives of any of the plurality of arrays, excepting said one array in which a failure was detected.

11. The method of claim 9, wherein said combining comprises configuring the new array as a RAID device.

12. The method of claim 11, wherein the RAID device is a RAID-4 device.

13. The method of claim 11, wherein the RAID device is a RAID-5 device.

14. The method of claim 9, wherein said grouping comprises maximizing the number of arrays of the plurality of arrays that comprise mirrored pairs of disk drives.

15. The method of claim 9, wherein said grouping comprises maximizing the number of arrays of the plurality of arrays that are configured as RAID devices including three disk drives.

16. The method of claim 9, wherein said grouping comprises a combination of at least two of:

arrays of mirrored pairs of disk drives, arrays in a RAID configuration of three disk drives and arrays in a RAID configuration having more than three disk drives.

17. The method of claim 9, wherein said combined arrays both comprised mirrored pairs of disk drives prior to said combining, and wherein said new array is configured as a RAID device.

18. The method of claim 9, wherein said one array comprises a mirrored pair of disk drives, wherein said another array is configured as a RAID device, and wherein the new array is configured as a RAID device.

19. A system, comprising:

a plurality of disk drives; and

an array controller, wherein the array controller comprises;

a processor; and

a memory coupled to the processor, wherein the memory comprises program instructions configured to implement;

grouping the plurality of disk drives into a plurality of arrays, each comprising a plurality of disk drives, and each array providing data redundancy within the respective array;

detecting a failure of a disk drive in one array of the plurality of arrays; and

in response to said detecting a failure, combining said one array with another array of the plurality of arrays into a new array comprising all non-failed disk drives of the two combined arrays.

20. The system of claim 19, wherein said another array comprises the smallest number of disk drives of any of the plurality of arrays, excepting said one array in which a failure was detected.

21. The system of claim 19, wherein as part of said combining, the program instructions are configured to configure the new array as a RAID device.

22. The system of claim 21, wherein the RAID device is a RAID-4 device.

23. The system of claim 21, wherein the RAID device is a RAID-5 device.

24. The system of claim 19, wherein as part of said grouping, the program instructions are configured to maximize the number of arrays of the plurality of arrays that comprise mirrored pairs of disk drives.

25. The system of claim 19, wherein as part of said grouping, the program instructions are configured to maximize the number of arrays of the plurality of arrays that are configured as RAID devices including three disk drives.

26. The system of claim 19, wherein as part of said grouping, the program instructions are configured to include in the plurality of arrays at least two of:

arrays of mirrored pairs of disk drives, arrays in a RAID configuration of three disk drives and arrays in a RAID configuration having more than three disk drives.

27. The system of claim 19, wherein said combined arrays both comprise mirrored pairs of disk drives, and wherein the new array is configured as a RAID device.

28. The system of claim 19, wherein said one array comprises a mirrored pair of disk drives, wherein said another array is configured as a RAID device, and wherein the new array is configured as a RAID device.

29. A computer accessible medium comprising program instructions configured to implement:

grouping a plurality of disk drives into a plurality of arrays, each comprising a plurality of disk drives, and each array providing data redundancy within the respective array;

detecting a failure of a disk drive in one array of the plurality of arrays; and

in response to said detecting a failure, combining said one array with another array of the plurality of arrays into a new array comprising all non-failed disk drives of the two combined arrays.

30. The computer accessible medium of claim 29, wherein said another array comprises the smallest number of disk drives of any of the plurality of arrays, excepting said one array in which a failure was detected.

31. The computer accessible medium of claim 29, wherein said combining comprises configuring the new array as a RAID device.

32. The computer accessible medium of claim 31, wherein the RAID device is a RAID-4 device.

33. The computer accessible medium of claim 31, wherein the RAID device is a RAID-5 device.

34. The computer accessible medium of claim 29, wherein as part of said grouping, the program instructions are configured to implement maximizing the number of arrays of the plurality of arrays that comprise mirrored pairs of disk drives.

35. The computer accessible medium of claim 29, wherein as part of said grouping, the program instructions are configured to implement maximizing the number of arrays of the plurality of arrays that are configured as RAID devices including three disk drives.

36. The computer accessible medium of claim 29, wherein as part of said grouping, the program instructions are configured to implement including in the plurality of arrays at least two of:

arrays of mirrored pairs of disk drives, arrays in a RAID configuration of three disk drives and arrays in a RAID configuration having more than three disk drives.

37. The computer accessible medium of claim 29, wherein said combined arrays both comprise mirrored pairs of disk drives, and wherein the new array is configured as a RAID device.

38. The computer accessible medium of claim 29, wherein said one array comprises a mirrored pair of disk drives, wherein said another array is configured as a RAID device, and wherein the new array is configured as a RAID device.