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

• US 7,398,354 B2
• Filed: 01/21/2005
• Issued: 07/08/2008
• Est. Priority Date: 01/21/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Wightwick, Glenn R, Wilson, Steven B, Jones, Carl E
• Primary Examiner(s): Thai; Tuan V.
• Application Number:
  US11/040,741
• Publication Number:
  US 20060168397A1
• Time in Patent Office: 1,264 Days
• Field of Search: 711/161, 711/100, 711/114, 711/154, 711/162, 711/201, 711/202, 711/203, 711/204
• 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, the method comprising:

receiving first data associated with a logical volume;

sending the first data over I/O channels in a striped fashion for storage across more than one physical source volume;

storing the first data on the more than one physical source volume;

receiving a first point-in-time copy command concerning the first data;

distributing the first point-in-time copy command over the I/O channels to each of the physical source volumes;

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

receiving second data associated with the logical volume to update the first data;

sending the second data over the I/O channels in a striped fashion for storage across the more than one physical source volume;

executing the distributed first point-in-time copy command by copying the first data stored on each physical source volume to the corresponding physical target volume; and

storing the second data on a physical source volume after the first data has been copied to the corresponding physical target volume.

2. The method of claim 1, wherein the I/O channels comprise in-band I/O channels maintained between a storage controller and the physical source volumes and across which read and write I/O operations are distributed.

3. The method of claim 1 further comprising:

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

receiving multiple point-in-time copy commands concerning the multiple updates, 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, whereby an update is stored to a physical source volume only after a previous update is copied from the physical source volume to the corresponding physical target volume.