Method, apparatus and program storage device for providing an optimized read methodology for synchronously mirrored virtual disk pairs

• US 20060218360A1
• Filed: 03/22/2005
• Published: 09/28/2006
• Est. Priority Date: 03/22/2005
• Status: Abandoned Application

• Current Assignee: Xiotech Corporation
• Original Assignee: Xiotech Corporation
• Inventors: Burkey, Todd R.
• Application Number:
  US11/086,079
• Publication Number:
  US 20060218360A1
• Time in Patent Office: Days
• US Class Current: 711/154
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A method, apparatus and program storage device for providing an optimized read methodology for synchronously mirrored virtual disk pairs are disclosed. A VDisk to use for read operations is determined based on loading of synchronously mirrored VDisk pairs. Based on the loading, the determined request is used to satisfy the read operation.

Claims

1. A method for performing read operations in a synchronously mirrored pair of virtual disks, comprising:

determining a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs; and

based on the loading, using the determined request to satisfy the read operation.

2. The method of claim 1, wherein the determining further comprises monitoring loading on physical disks of the virtual disks;

and

determining whether the loading of the source virtual disk is too great.

3. The method of claim 2, wherein the using the determined request further comprises continuing to monitor the loading of the physical disks when loading of the source virtual disk is not too great.

4. The method of claim 2, wherein the using the determined request further comprises switching read operation to the destination virtual disk when loading of the source virtual disk is too great.

5. The method of claim 1, wherein the determining further comprises issuing reads simultaneously to both a source and destination virtual disk and monitoring the virtual disks for the first request to return.

6. The method of claim 1, wherein the using the determined request further comprises using the first request to return and canceling the read operation not returning from the source and destination virtual disk.

7. A controller for performing read operations in a synchronously mirrored pair of virtual disks, comprising:

memory for storing data and program operation instructions thereon; and

a processor, coupled to the memory, the processor being configured to determine a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs and based on the loading, to use the determined request to satisfy the read operation.

8. The controller of claim 7, wherein the controller determines a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs by monitoring loading on physical disks of the virtual disks and determining whether the loading of the source virtual disk is too great.

9. The controller of claim 8, wherein the controller continuing to monitor the loading of the physical disks when loading of the source virtual disk is not too great.

10. The controller of claim 8, wherein the controller switches read operation to the destination virtual disk when loading of the source virtual disk is too great.

11. The controller of claim 7, wherein the controller determines a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs by issuing reads simultaneously to both a source and destination virtual disk and monitoring the virtual disks for the first request to return.

12. The controller of claim 7, wherein the controller uses the first request to return and cancels the read operation not returning from the source and destination virtual disk.

13. A storage system, comprising:

a pool of storage devices; and

a controller, coupled to the pool of storage devices, the controller virtualizing physical disks in the pool of storage devices as virtual disks, a first virtual disk being synchronously mirrored to a second virtual disk, wherein the controller determines whether to use the first or second virtual disk for read operations based on loading of the first and second virtual disk and based on the loading, uses the determined request to satisfy the read operation.

14. The storage system of claim 13, wherein the controller determines a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs by monitoring loading on physical disks of the virtual disks and determining whether the loading of the source virtual disk is too great.

15. The storage system of claim 14, wherein the controller continuing to monitor the loading of the physical disks when loading of the source virtual disk is not too great.

16. The storage system of claim 14, wherein the controller switches read operation to the destination virtual disk when loading of the source virtual disk is too great.

17. The storage system of claim 13, wherein the controller determines a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs by issuing reads simultaneously to both a source and destination virtual disk and monitoring the virtual disks for the first request to return.

18. The storage system of claim 13, wherein the controller uses the first request to return and cancels the read operation not returning from the source and destination virtual disk.

19. A program storage device, comprising:

program instructions executable by a processing device to perform operations for performing read operations in a synchronously mirrored pair of virtual disks, the operations comprising;

determining a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs; and

based on the loading, using the determined request to satisfy the read operation.

20. The program storage device of claim 19, wherein the determining further comprises

monitoring loading on physical disks of the virtual disks;

and

determining whether the loading of the source virtual disk is too great.

21. The program storage device of claim 20, wherein the using the determined request further comprises continuing to monitor the loading of the physical disks when loading of the source virtual disk is not too great.

22. The program storage device of claim 20, wherein the using the determined request further comprises switching read operation to the destination virtual disk when loading of the source virtual disk is too great.

23. The program storage device of claim 19, wherein the determining further comprises issuing reads simultaneously to both a source and destination virtual disk and monitoring the virtual disks for the first request to return.

24. The program storage device of claim 19, wherein the using the determined request further comprises using the first request to return and canceling the read operation not returning from the source and destination virtual disk.

25. A controller for performing read operations in a synchronously mirrored pair of virtual disks, comprising:

means for storing data and program operation instructions thereon; and

means, coupled to the means for storing data and program operation instructions, for determining a virtual disk to use for read operations based on loading of synchronously mirrored virtual disk pairs and based on the loading, for using the determined request to satisfy the read operation.

26. A controller for performing read operations in a synchronously mirrored pair of virtual disks, comprising:

memory for storing data and program operation instructions thereon; and

a processor, coupled to the memory, the processor being configured to issue the read request to both source and destination VDisks simultaneously and then process whichever read operation completes or, based on queue management, appears to be going to complete first.

27. The controller of claim 26, wherein controller issues the read request based upon virtual disk loading.

28. The controller of claim 26, wherein controller cancels a request not completing first.