Method of and system for testing remote storage

• US 20060075148A1
• Filed: 09/21/2004
• Published: 04/06/2006
• Est. Priority Date: 09/21/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Osaki, Nobuyuki
• Granted Patent: US 7,139,782 B2
• Time in Patent Office: Days
• US Class Current: 710/5
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

A remote backup storage system that may be tested with current backup data while the remote system continues to received data from a primary source data storage system includes a remotely located front-end volume that is connected to receive data from a source volume. A remotely located secondary volume normally receives data from the front-end volume. The secondary volume is the volume to which data of the source volume is backed up. The front-end volume serves as buffer for data transferred from the source volume to the secondary volume. A third volume that is used to preserve or restore the data in the secondary volume during a test.

Claims

1. A storage system, which comprises:

a first volume connected to receive data from a source volume;

a second volume;

means for transferring data from said first volume to said second volume;

means for suspending transfer of data from said first volume to said second volume in response to instructions to accept test I/O requests;

means for servicing, with said second volume, I/O requests from a secondary host computer during suspension of transfer of data from said first volume to said second volume; and

,

means for resuming transfer of data from said first volume to said second volume in response to instructions to stop accepting test I/O requests.

2. The storage system as claimed in claim 1, wherein said means for servicing I/O requests includes:

a third volume.

3. The system as claimed in claim 2, including:

means for creating in said third volume a snapshot of said second volume in response to said instructions to accept test I/O requests.

4. The system as claimed in claim 3, including:

means for servicing with said second volume read requests.

5. The system as claimed in claim 3, including:

means for servicing from said second volume write requests.

6. The system as claimed in claim 5, including:

means for determining if a record to be written is in said snapshot.

7. The system as claimed in claim 3 including:

means for restoring said second volume in response to instructions to stop accepting test I/O requests.

8. The system as claimed in claim 2, including:

means for servicing write requests with said third volume.

9. The system as claimed in claim 8, including:

means for determining if record subject to a read request is in said third volume.

10. The system as claimed in claim 9, including:

means for servicing said read request from said third volume if the record to be read is in said third volume.

11. The system as claimed in claim 9, including:

means for servicing said read request from said second volume if the record to be read is not in said third volume.

12. The system as claimed in claim 2, including:

means for clearing said third volume in response to said instructions to stop accepting test I/O requests.

13. A method of providing backup services, which comprises:

receiving data from a source volume at a remotely located first volume;

transferring data from said first volume to a remotely located second volume;

suspending transfer of data from said first volume to said second volume in response to instructions to accept test I/O requests;

servicing, with said second volume, I/O requests from a secondary host system during suspension of transfer of data from said first volume to said second volume, and,

resuming transfer of data from first volume to said second volume in response to instructions to stop accepting test I/O requests.

14. The method as claimed in claim 13, including:

creating a snapshot of said second volume in response to said instructions to accept test I/O requests.

16. The method as claimed in claim 13, wherein servicing I/O requests with said second volume includes:

accepting read and write requests.

17. The method as claimed in claim 16, including:

prior to servicing a write request, determining if the record to be written is in said snapshot;

if said record to be written is not in said snapshot, copying said record to be written from said second volume to said snapshot before writing said record to be written in said second volume.

18. The method as claimed in claim 14, including:

restoring said second volume with said snapshot in response to said instructions to stop accepting test I/O requests.

19. The method as claimed in claim 18, including clearing said snapshot after restoring said second volume.

20. The method as claimed in claim 13, including:

in response to a write request, writing a record in an alternate volume.

21. The method as claimed in claim 20, including:

in response to a read request, determining if the record to be read is in said alternate volume;

reading the record to be read from said alternate volume if said record to be read is in said alternate volume; and

,

reading the record to be read from said second volume if said record to be read is not in said alternate volume.

22. The method as claimed in claim 21, including:

clearing said alternate volume in response to instructions to stop accepting test I/O requests.

15. (canceled)

23-32. -32. (canceled)