Achieving data consistency with point-in-time copy operations in a parallel I/O environment

• US 20060168397A1
• Filed: 01/21/2005
• Published: 07/27/2006
• Est. Priority Date: 01/21/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jones, Carl E., Wilson, Steven B., Wightwick, Glenn R.
• Granted Patent: US 7,398,354 B2
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1458 Management of the backup or restore process
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A method for processing a point-in-time copy of data associated with a logical storage volume where the data to be copied is stored in a striped or parallelized fashion across more than one physical source volume. The method includes receiving a point-in-time copy command concerning a logical volume and distributing the point-in-time copy command in-band to each of the physical source volumes containing a portion of the striped data. The method also includes establishing a point-in-time copy relationship between each physical source volume and one of a corresponding set of multiple physical target volumes. The method further includes copying the data stored on each physical source volume to the corresponding physical target volume. The in-band copy command and the striped data may be distributed over I/O channels between a server and the physical storage and processed sequentially.

Claims

1. A method of processing a point-in-time copy of data associated with a logical storage volume, wherein the data is stored on more than one physical source volume, the method comprising:

receiving a point-in-time copy command concerning the logical volume;

distributing the point-in-time copy command to each of the physical source volumes;

establishing a point-in-time copy relationship between each physical source volume and one of a corresponding set of more than one physical target volumes; and

copying the data stored on each physical source volume to the corresponding physical target volume.

2. The method of claim 1 further comprising:

receiving an update to the data associated with the logical volume after the point-in-time copy relationship between each physical source volume and corresponding physical target volume is established;

parallelizing the update;

distributing the update to each physical source volume; and

writing the update to each physical source volume after the data stored on that physical source volume has been copied to the corresponding physical target volume.

3. The method of claim 2 further comprising:

distributing the point-in-time copy command to each physical source volume over I/O channels maintained between a storage controller and the physical source volumes.

4. The method of claim 3 further comprising distributing the update to each physical source volume over the I/O channels and executing the point-in-time copy command and the write of the update sequentially.

5. The method of claim 1 further comprising:

receiving multiple updates to the data associated with the logical volume;

receiving multiple point-in-time copy commands concerning the data with the multiple point-in-time copy commands and multiple updates being received in a sequence;

parallelizing the updates;

distributing the updates to each of the physical source volumes;

distributing the point-in-time copy commands to each of the physical source volumes; and

writing the updates to each physical source volume and executing the point-in-time copy commands with respect to each physical source volume in accordance with the sequence.

6. The method of claim 5 further comprising:

distributing the point-in-time copy commands to each physical source volume over I/O channels maintained between a storage controller and the physical source volumes; and

distributing the updates to each physical source volume over the I/O channels.

7. A data storage system comprising:

a storage server capable of processing an I/O write command and a point-in-time copy command each with respect to a logical storage volume.

multiple physical source volumes in communication with the storage server, each capable of being established in a point-in-time copy relationship with one of corresponding multiple physical target volumes;

a logical volume manager associated with the storage server capable of parallelizing data associated with the I/O write command and distributing a portion of the data for writing to each of the multiple physical storage volumes, the logical volume manager being further capable of distributing the point-in-time copy command to each of the physical source volumes.

8. The data storage system of claim 7 further comprising means for:

receiving an update to the data associated with the logical volume after a point-in-time copy relationship between each physical source volume and corresponding physical target volume is established;

parallelizing the update;

distributing the update to each physical source volume; and

writing the update to each physical source volume after the data stored on that physical source volume has been copied to the corresponding physical target volume.

9. The data storage system of claim 8 further comprising data storage system I/O channels maintained between the storage controller and the physical source volumes.

10. The data storage system of claim 9 further comprising means for sending the update to each physical source volume over the I/O channels and executing the point-in-time copy command and the write of the update sequentially.

11. The data storage system of claim 7 further comprising means for:

receiving multiple updates to the data;

receiving multiple point-in-time copy commands concerning the data with the multiple point-in-time copy commands and multiple updates being received in a sequence;

parallelizing the updates;

distributing the updates to each of the physical source volumes;

distributing the point-in-time copy commands to each of the physical source volumes; and

writing the updates to each physical source volume and executing the point-in-time copy commands with respect to each physical source volume in accordance with the sequence.

12. The data storage system of claim 11 further comprising:

one or more I/O channels providing for communication between the storage controller and the physical source volumes;

means for distributing the point-in-time copy commands to each physical source volume over the I/O channels;

means for distributing the updates to each physical source volume over the I/O channels.

13. An article of manufacture for use in programming a data storage system to process a point-in-time copy of data associated with a logical storage volume, wherein the data is stored on more than one physical source volume, the article of manufacture comprising instructions for:

receiving a point-in-time copy command concerning the logical volume;

distributing the point-in-time copy command to each of the physical source volumes;

establishing a point-in-time copy relationship between each physical source volume and one of a corresponding set of more than one physical target volumes; and

copying the data stored on each physical source volume to the corresponding physical target volume.

14. The article of manufacture of claim 13 further comprising instructions for:

receiving an update to the data associated with the logical volume after the point-in-time copy relationship between each physical source volume and corresponding physical target volume is established;

parallelizing the update;

distributing the update to each physical source volume; and

writing the update to each physical source volume after the data stored on that physical source volume has been copied to the corresponding physical target volume.

15. The article of manufacture of claim 14 further comprising instructions for:

distributing the point-in-time copy command to each physical source volume over I/O channels maintained between a storage controller and the physical source volumes.

16. The article of manufacture of claim 15 further comprising instructions for distributing the update to each physical source volume over the I/O channels and executing the point-in-time copy command and the write of the update sequentially.

17. The article of manufacture of claim 13 further comprising instructions for:

receiving multiple updates to the data associated with the logical volume;

receiving multiple point-in-time copy commands concerning the data with the multiple point-in-time copy commands and multiple updates being received in a sequence;

parallelizing the updates;

distributing the updates to each of the physical source volumes;

distributing the point-in-time copy commands to each of the physical source volumes; and

writing the updates to each physical source volume and executing the point-in-time copy commands with respect to each physical source volume in accordance with the sequence.

18. The article of manufacture of claim 17 further comprising instructions for:

distributing the point-in-time copy commands to each physical source volume over I/O channels maintained between a storage controller and the physical source volumes; and

distributing the updates to each physical source volume over the I/O channels.