System and method for striped mirror re-synchronization by logical partition rather than stripe units

• US 6,662,268 B1
• Filed: 09/02/1999
• Issued: 12/09/2003
• Est. Priority Date: 09/02/1999
• Status: Expired due to Term

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: McBrearty, Gerald Francis, Shieh, Johnny Meng-Han
• Primary Examiner(s): NGUYEN, THAN VINH
• Application Number:
  US09/388,951
• Time in Patent Office: 1,559 Days
• Field of Search: 711/111, 711/112, 711/114, 711/161, 711/162
• US Class Current: 711/114
• CPC Class Codes: G06F 11/2082 Data synchronisation

Abstract

Striped mirrors are re-synchronized by logical partition rather than by stripe unit for stale partitions. While re-synchronizing physical partitions, data is serialized across both the stripe unit and the real partition region. The re-sync Read operation uses the normal logical partition offsets to read on a physical partition boundary rather than using the stripe units. In so doing, a single disk in a striped mirror can be replaced without re-synchronizing the entire mirror. The resync Read is not broken up into individual stripe unit reads.

Claims

1. A data processing system implemented method for resynchronizing a striped mirror, comprising:

receiving information that a disk is stale, wherein the disk is associated with a mirror; and

performing a resynchronizing Read for a block on only the stale disk, wherein prior to performing a resynchronizing Read, the method comprises;

serializing an IO request across both a stripe unit and a partition boundary.

2. The method recited in claim 1, wherein performing a resynchronizing Read further comprises:

determining an active mirror for the block;

reading the block from an active partition on the active mirror; and

writing the block to the stale partition on the stale disk.

3. The method recited in claim 2, wherein reading the block further comprises:

reading the block from the active partition as a single Read.

4. The method recited in claim 2, wherein reading the block further comprises:

reading the block on a real partition boundary on the active partition.

5. The method recited in claim 2, wherein reading the block further comprises:

reading the entire block from the active partition.

6. The method recited in claim 2, wherein reading the block further comprises:

reading the entire block as a single re-sync request.

7. The method recited in claim 2, wherein writing the block further comprises:

writing the block to the stale partition as a single Write.

8. The method recited in claim 2, wherein writing the block further comprises:

writing the block to a real partition boundary on the stale partition.

9. The method recited in claim 2, wherein reading the block further comprises:

writing the entire block as a single re-sync request.

10. A data processing system implemented method for resynchronizing a striped mirror, comprising:

serializing IO requests to both a logical region boundary and stripe units

issuing a re-sync Read IO request for a block;

determining an available mirror for the block;

issuing a single Read for reading the block from a boundary on a first disk, wherein the first disk is associated with the available mirror; and

issuing a single Write for writing the block from a boundary on a second disk, wherein the second disk is stale.

11. A data processing system implemented method for resynchronizing a striped mirror, comprising:

issuing a Read IO request for a first block;

determining at least two stripe units associated with the first block;

identifying a physical region for each stripe unit;

issuing separate Read IO requests for each stripe unit associated with the block for each physical region;

issuing a re-sync Read IO request for a second block;

determining an available mirror for the second block;

issuing a single Read IO request for reading the second block from a boundary on a second physical region, wherein the second physical region is associated with the available mirror; and

issuing a single Write IO request for writing the second block from a boundary on a third region, wherein the third region is stale.

12. A data processing system for resynchronizing a striped mirror, comprising:

receiving means for receiving information that a disk is stale, wherein the disk is associated with a mirror;

performing means for perform a resynchronizing Read for a block on only the stale disk; and

serializing means for serializing an IO request across both a stripe unit and a partition boundary.

13. The system recited in claim 12, wherein the performing means for performing a resynchronizing Read further comprises:

determining means for determining an active mirror for the block;

reading means for reading the block from an active partition on the active mirror; and

writing means for writing the block to the stale partition on the stale disk.

14. The system recited in claim 13, wherein the reading means for reading the block further comprises:

reading means for reading the block from the active partition as a single Read.

15. The system recited in claim 14, wherein the reading means for reading the block further comprises:

reading means for reading the block on a real partition boundary on the active partition.

16. The system recited in claim 13, wherein the reading means for reading the block further comprises:

reading means for reading the entire block from the active partition.

17. The system recited in claim 13, wherein the reading means for reading the block further comprises:

reading means for reading the entire block as a single re-sync request.

18. The system recited in claim 13, wherein the writing means for writing the block further comprises:

writing means for writing the block to the stale partition as a single Write.

19. The system recited in claim 13, wherein the writing means for writing the block further comprises:

writing means for writing the block to a real partition boundary on the stale partition.

20. The system recited in claim 13, wherein the reading means for reading the block further comprises:

writing means for writing the entire block as a single re-sync request.

21. A data processing system for resynchronizing a striped mirror, comprising:

serializing means for serializing IO requests to both stripe units and a logical region boundary;

issuing means for issuing a re-sync Read IO request for a block;

determining means for determining an available mirror for the block;

issuing means for issuing a single Read for reading the block from a boundary on a first disk, wherein the first disk is associated with the available mirror; and

issuing means for issuing a single Write for writing the block from a boundary on a second disk, wherein the second disk is stale.

22. A data processing system for resynchronizing a striped mirror, comprising:

issuing means for issuing a Read request IO request for a first block;

determining means for determining at least two stripe units associated with the first block;

identifying means for identifying a physical region for each stripe unit;

issuing means for issuing separate Reads for each stripe unit associated with the block for each physical region;

issuing means for issuing a re-sync Read IO request for a second block;

determining an available mirror for the second block;

issuing means for issuing a single Read for reading the second block from a boundary on a second physical region, wherein the second physical region is associated with the available mirror; and

issuing means for issuing a single Write for writing the second block from a boundary on a third region, wherein the third region is stale.

23. A computer program product for implementing a method for resynchronizing a striped mirror, comprising:

receiving instructions for receiving information that a disk is stale, wherein the disk is associated with a mirror;

performing instructions for performing a resynchronizing Read for a block on only the stale disk; and

serializing instructions for serializing an IO request across both a stripe unit and a partition boundary.