Data recovery for virtual ordered writes for multiple storage devices

• US 20050132248A1
• Filed: 12/01/2003
• Published: 06/16/2005
• Est. Priority Date: 12/01/2003
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Meiri, David, Halstead, Mark J., Lecrone, Douglas E., Longinov, Vadim, Heasley, Kevin C.
• Granted Patent: US 7,228,456 B2
• Time in Patent Office: Days
• US Class Current: 714/5
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2082 Data synchronisation

Abstract

Recovering data provided in chunks to a plurality of secondary storage devices includes, for each of the secondary storage devices, discarding data corresponding chunks for which all data thereof has not been received, and, for each of the secondary storage devices, restoring a chunk of data thereto where all of the chunks of data restored to the plurality of secondary storage devices correspond to a particular transmission cycle of primary storage devices that provide data to the plurality of secondary storage devices. Recovering data may also include, following discarding and prior to restoring, for each of the plurality of secondary storage devices having two different chunks, waiting for external intervention to indicate whether to restore a particular one of the chunks. The external intervention may be provided by a host computer that is proximate to at least one of the secondary storage devices or may be provided by a host computer that is proximate to at least one of the primary storage computers.

Claims

1. A method of recovering data provided in chunks to a plurality of secondary storage devices, comprising:

for each of the secondary storage devices, discarding data corresponding chunks for which all data thereof has not been received; and

for each of the secondary storage devices, restoring a chunk of data thereto wherein all of the chunks of data restored to the plurality of secondary storage devices correspond to a particular transmission cycle of primary storage devices that provide data to the plurality of secondary storage devices.

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

following discarding and prior to restoring, for each of the plurality of secondary storage devices having two different chunks, waiting for external intervention to indicate whether to restore a particular one of the chunks.

3. A method, according to claim 2, wherein the external intervention is provided by a host computer that is proximate to at least one of the secondary storage devices.

4. A method, according to claim 2, wherein the external intervention is provided by a host computer that is proximate to at least one of the primary storage computers.

5. A method, according to claim 2, further comprising:

restoring most recent chunks for all of the plurality of secondary storage devices in response to there being two different chunks associated with all of the plurality of secondary storage devices, wherein a first one of the two chunks corresponds to a first transmission cycle and wherein a second one of the two chunks corresponding to a different transmission cycle.

6. A method, according to claim 5, further comprising:

discarding chunks that are not restored.

7. A method, according to claim 2, further comprising:

for each of the secondary storage devices, restoring a chunk of data corresponding to a particular transmission cycle wherein all of the secondary storage devices contain a chunk of data corresponding to the particular transmission cycle.

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

discarding chunks that are not restored.

9. A method, according to claim 1, wherein each transmission cycle is assigned a particular tag value that is provided with each chunk of data.

10. A method, according to claim 9, wherein the tag values are used to determine the particular cycle for each of the chunks of data.

11. Computer software that recovers data provided in chunks to a plurality of secondary storage devices, comprising:

executable code that discards data corresponding chunks for which all data thereof has not been received for each of the secondary storage devices; and

executable code that restores a chunk of data thereto for each of the secondary storage devices, wherein all of the chunks of data restored to the plurality of secondary storage devices correspond to a particular transmission cycle of primary storage devices that provide data to the plurality of secondary storage devices.

12. Computer software, according to claim 11, further comprising:

executable code that waits for external intervention to indicate whether to restore a particular one of the chunks for each of the plurality of secondary storage devices having two different chunks.

13. Computer software, according to claim 12, further comprising:

executable code that restores most recent chunks for all of the plurality of secondary storage devices in response to there being two different chunks associated with all of the plurality of secondary storage devices, wherein a first one of the two chunks corresponds to a first transmission cycle and wherein a second one of the two chunks corresponding to a different transmission cycle.

14. Computer software, according to claim 13, further comprising:

executable code that discards chunks that are not restored.

15. Computer software, according to claim 12, further comprising:

executable code that restores a chunk of data corresponding to a particular transmission cycle wherein all of the secondary storage devices contain a chunk of data corresponding to the particular transmission cycle.

16. Computer software, according to claim 15, further comprising:

executable code that discards chunks that are not restored.

17. Computer software, according to claim 11, wherein each transmission cycle is assigned a particular tag value that is provided with each chunk of data.

18. Computer software, according to claim 17, wherein the tag values are used to determine the particular cycle for each of the chunks of data.