Reversing a communication path between storage devices

• US 6,976,139 B2
• Filed: 11/30/2001
• Issued: 12/13/2005
• Est. Priority Date: 11/14/2001
• Status: Expired due to Term

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Meiri, David, Arnon, Dan, Halstead, Mark J.
• Primary Examiner(s): CHACE, CHRISTIAN
• Application Number:
  US09/998,683
• Publication Number:
  US 20030172227A1
• Time in Patent Office: 1,474 Days
• Field of Search: 707/10, 707/201, 707/202, 707/203, 707/204, 710/31, 710/32, 710/33, 710/38, 710/316, 710/240, 711/111, 711/147, 711/154, 711/161, 711/162, 714/4, 714/6, 714/43, 714/748, 714/749, 714/769, 709/208, 709/217, 709/229
• US Class Current: 711/161
• CPC Class Codes: G06F 11/1666 where the redundant component is memory or memory area
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

Reversing a communication path between a first volume on a first storage device and a second volume on a second storage device includes suspending communication between the first and second volumes while maintaining operations for other volumes of the storage devices, causing the first volume to change from a source volume to a destination volume without destroying the first volume, causing the second volume to change from a destination volume to a source volume without destroying the second volume, and resuming communication between the first and second volumes. Causing the first volume to change from a source volume to a destination volume may include modifying a table of the first storage device. Causing the second volume to change from a source volume to a destination volume may include modifying a table of the second storage device.

Claims

1. A method of reversing a communication path between a first volume on a first storage device and a second volume on a second storage device, comprising:

suspending communication between the first and second volumes while maintaining operations for other volumes of the storage devices;

causing the first volume to change from a source volume to a destination volume without destroying the first volume;

causing the second volume to change from a destination volume to a source volume without destroying the second volume;

after causing the first volume to change from a source volume to a destination volume and causing the second volume to change from a destination volume to a source volume, initiating a background copy of data from the source volume to the destination volume; and

resuming data access operations to the first and second volumes independent of completion of the background copy, wherein, in response to a data access operation to the second volume and valid data for the data access operation existing only on the first volume, the data access operation to the second volume is satisfied by accessing data from the first volume and wherein, in response to a write of particular data to the second volume, the particular data is transferred from the second volume to the first volume irrespective of whether the background copy is complete.

2. A method, according to claim 1, wherein causing the first volume to change from a source volume to a destination volume includes modifying a table of the first storage device.

3. A method, according to claim 2, wherein causing the second volume to change from a source volume to a destination volume includes modifying a table of the second storage device.

4. A method, according to claim 1, wherein suspending communication includes setting the first volume to a not ready state.

5. A method, according to claim 4, wherein resuming communication includes setting the second volume to a ready state.

6. A method, according to claim 1, further comprising:

returning a result indicating successfully reversing the communication path.

7. A method of managing volumes on storage devices, comprising:

receiving a command requesting reversal of a communication path between a first volume on a first storage device and a second volume on a second storage device;

suspending communication between the first and second volumes while maintaining operations for other volumes of the storage devices;

causing the first volume to change from a source volume to a destination volume without destroying the first volume;

causing the second volume to change from a destination volume to a source volume without destroying the second volume;

after causing the first volume to change from a source volume to a destination volume and causing the second volume to change from a destination volume to a source volume, initiating a background copy of data from the source volume to the destination volume; and

resuming data access operations to the first and second volumes independent of completion of the background copy, wherein, in response to a data access operation to the second volume and valid data for the data access operation existing only on the first volume, the data access operation to the second volume is satisfied by accessing data from the first volume and wherein, in response to a write of particular data to the second volume, the particular data is transferred from the second volume to the first volume irrespective of whether the background copy is complete.

8. A method, according to claim 7, wherein the command is a single multihop, multiexecute command that causes operations to be performed on the first and second storage devices.

9. A method, according to claim 7, wherein causing the first volume to change from a source volume to a destination volume includes modifying a table of the first storage device.

10. A method, according to claim 9, wherein causing the second volume to change from a source volume to a destination volume includes modifying a table of the second storage device.

11. A method, according to claim 7, wherein suspending communication includes setting the first volume to a not ready state.

12. A method, according to claim 11, wherein resuming communication includes setting the second volume to a ready state.

13. A method, according to claim 7, further comprising:

returning a result indicating successfully reversing the communication path.

14. A computer program product stored on a tangibly embodied computer-readable medium, executed by a processor that reverses a communication path between a first volume on a first storage device and a second volume on a second storage device, comprising:

executable code that suspends communication between the first and second volumes while maintaining operations for other volumes of the storage devices;

executable code that causes the first volume to change from a source volume to a destination volume without destroying the first volume;

executable code that causes the second volume to change from a destination volume to a source volume without destroying the second volume;

executable code that initiates a background copy of data from the source volume to the destination volume after causing the first volume to change from a source volume to a destination volume and causing the second volume to change from a destination volume to a source volume; and

executable code that resumes data access operations to the first and second volumes independent of completion of the background copy, wherein, in response to a data access operation to the second volume and valid data for the data access operation existing only on the first volume, the data access operation to the second volume is satisfied by accessing data from the first volume and wherein, in response to a write of particular data to the second volume, the particular data is transferred from the second volume to the first volume irrespective of whether the background copy is complete.

15. A computer program product, according to claim 14, wherein executable code that causes the first volume to change from a source volume to a destination volume modifies a table of the first storage device.

16. A computer program product, according to claim 15, wherein executable code that causes the second volume to change from a source volume to a destination volume modifies a table of the second storage device.

17. A computer program product, according to claim 14, wherein executable code that suspends communication sets the first volume to a not ready state.

18. A computer program product, according to claim 17, wherein executable code that resumes communication sets the second volume to a ready state.

19. A computer program product, according to claim 14, further comprising:

executable code that returns a result indicating successfully reversing the communication path.