Method and apparatus for managing data access and storage of data located on multiple storage devices

• US 6,708,237 B1
• Filed: 11/09/2001
• Issued: 03/16/2004
• Est. Priority Date: 01/15/1999
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Bridge, William
• Primary Examiner(s): ELAMIN, ABDELMONIEM I
• Application Number:
  US10/008,347
• Time in Patent Office: 858 Days
• Field of Search: 710/39, 360/90, 711/114, 711/165
• US Class Current: 710/39
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

An apparatus and method for accessing a data item from a storage system having a plurality of data storage devices are disclosed. I/O operation requests are submitted to multiple data storage devices for each data item to be accessed. The I/O operation requests are issued to copies of the data items that reside on a plurality of data storage devices. More I/O operation requests are submitted than the number of data items that are to be accessed, written, or updated.

Claims

1. A method of writing a data item to a storage system having a plurality of data storage devices, the method comprising:

receiving a write request for writing a predetermined number of copies of said data item to said plurality of data storage devices; and

initiating write operation requests to a selected number of said plurality of data storage devices in response to said write request, the selected number exceeding said predetermined number.

2. The method of claim 1, further comprising identifying a first set of said write operation requests that are projected to produce a fastest response time.

3. The method of claim 2, further comprising canceling a second set of said write operation requests.

4. The method of claim 2, further comprising:

completing a second set of said write operation requests; and

deleting copies of said data item written by said second set of said write operation requests.

5. The method of claim 2, wherein identifying a first set of said write operation requests comprises identifying said first set of said write operation requests as being first to complete writing said data item to said selected number of said plurality of data storage devices.

6. The method of claim 2, wherein identifying a first set of said write operation requests comprises identifying said first set of said write operation requests as being first in moving from one level of request queues to another.

7. The method of claim 1, wherein receiving a write request comprises receiving said write request for writing said data item to at least two of said plurality of data storage devices.

8. A method of updating a data item in a storage system having a plurality of data storage devices, the method comprising:

receiving an update request for maintaining a predetermined number of copies of said data item in said plurality of data storage devices; and

initiating update operation requests to a selected number of said plurality of data storage devices in response to said update request, said selected number exceeding said predetermined number.

9. The method of claim 8, further comprising identifying a first set of said update operation requests that are projected to produce a fastest response time.

10. The method of claim 9, further comprising canceling a second set of said update operation requests.

11. The method of claim 9, further comprising:

completing a second set of said update operation requests; and

deleting copies of said data item written by said second set of said update operation requests.

12. The method of claim 9, wherein identifying a first set of said update operation requests comprises identifying said first set of said update operation requests as being first to update said data item to said selected number of said plurality of data storage devices.

13. The method of claim 9, wherein identifying a first set of said update operation requests comprises identifying said first set of said update operation requests as being first in moving from one level of request queues to another.

14. The method of claim 8, wherein initiating update operation requests comprises initiating at least one of said update operation requests for updating an existing copy of said data item on one of said plurality of data storage devices.

15. The method of claim 8, wherein initiating update operation requests comprises:

writing copies of said data item to new sections of said plurality of data storage devices; and

reconfiguring a plurality of pointers to point to said new sections of said plurality of data storage devices.

16. The method of claim 15, further comprising deleting copies of said data item in sections of said plurality of data storage devices that are no longer pointed to by said plurality of pointers.

17. A computer program product that includes a medium readable by a processor, the medium having stored thereon a sequence of instructions which, when executed by said processor, causes said processor to execute a process of writing a data item to a storage system having a plurality of data storage devices, said process:

receiving a write request for writing a predetermined number of copies of said data item to said plurality of data storage devices; and

initiating write operation requests to a selected number of said plurality of data storage devices in response to said write request, the selected number exceeding said predetermined number.

18. The computer program product of claim 17, wherein said process further comprises identifying a first set of said write operation requests that is are projected to produce a fastest response time.

19. The computer program product of claim 18, wherein said process further comprises canceling a second set of said write operation requests.

20. The computer program product of claim 18, wherein said process further comprises:

completing a second set of said write operation requests; and

deleting copies of said data item written by said second set of said write operation requests.

21. The computer program product of claim 18, wherein identifying a first set of said write operation requests comprises identifying said first set of said write operation requests as being first to complete writing said data item to said selected number of said plurality of data storage devices.

22. The computer program product of claim 18, wherein identifying a first set of said write operation requests comprises identifying said first set of said write operation requests as being first in moving from one level of request queues to another.

23. The computer program product of claim 17, wherein receiving a write request comprises receiving said write request for writing said data item to at least two of said plurality of data storage devices.

24. A computer program product that includes a medium readable by a processor, the medium having stored thereon a sequence of instructions which, when executed by said processor, causes said processor to execute a process of updating a data item stored in a storage system having a plurality of data storage devices, said process comprising:

receiving an update request for maintaining a predetermined number of copies of said data item in said plurality of data storage devices; and

initiating update operation requests to a selected number of said plurality of data storage devices in response to said update request, said selected number exceeding said predetermined number.

25. The computer program product of claim 24, wherein said process further comprises identifying a first set of said update operation requests that are projected to produce a fastest response time.

26. The computer program product of claim 25, wherein said process further comprises canceling a second set of said update operation requests.

27. The computer program product of claim 25, wherein said process further comprises:

completing a second set of said update operation requests; and

deleting copies of said data item written by said second set of said update operation requests.

29. The computer program product of claim 25, wherein identifying a first set of said update operation requests comprises identifying said first set of said update operation requests as being first in moving from one level of request queues to another.

30. The computer program product of claim 24, wherein initiating update operation requests comprises initiating at least one of said update operation requests for updating an existing copy of said data item on one of said plurality of data storage devices.

31. The computer program product of claim 24, wherein initiating update operation requests comprises:

writing copies of said data item to new sections of said plurality of data storage devices; and

reconfiguring a plurality of pointers to point to said new sections of said plurality of data storage devices.

32. The computer program product of claim 31, wherein said process further comprises deleting copies of said data item in sections of said plurality of data storage devices that are no longer pointed to by said plurality of pointers.

28. The computer program product of claims wherein identifying a first set of said update operation requests comprises identifying said first set of said update operation requests as being first to update said data item to said selected number of said plurality of data storage devices.