Remote copying system with consistency guaranteed between a pair

• US 7,225,190 B2
• Filed: 09/17/2004
• Issued: 05/29/2007
• Est. Priority Date: 04/23/2004
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Maki, Nobuhiro, Satoh, Takao, Iwamura, Takashige, Takahashi, Masamitsu
• Primary Examiner(s): Rimell; Sam
• Assistant Examiner(s): RADTKE, MARK A
• Application Number:
  US10/942,936
• Publication Number:
  US 20050240634A1
• Time in Patent Office: 984 Days
• Field of Search: 711/114, 711/161, 711/162, 714/6, 707/204
• US Class Current: 1/1
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 11/2074 Asynchronous techniques
• CPC Class Codes: G06F 11/2076 Synchronous techniques
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

When plural copy groups including pairs exist, remote copying for pairs belonging to copy groups is suspended selectively on a copy group-to-copy group basis, instead of suspending remote copying in all the copy groups at once. A computer system has a host computer, plural first storage systems comprising plural first logical disks, and plural second storage systems comprising plural second logical disks. A first logical disk and a second logical disk paired with the first logical disk, and each pair belongs to either a first copy group or a second copy group. To selectively suspend remote copying on a copy group-to-copy group basis, one of the copy groups is specified first and then pairs belonging to this copy group are designated. The first storage systems comprising first logical disks of the designated pairs suspend remote copy processing for the designated pairs.

Claims

1. A remote copy system comprising:

a copy group manager;

a plurality of first storage systems including a plurality of first logical disks and first controllers;

a plurality of second storage systems, coupled to the plurality of first storage systems, including a plurality of second logical disks and second controllers; and

a plurality of third storage systems, coupled to the plurality of first storage systems, including a plurality of third logical disks and third controllers;

wherein a plurality of synchronous type remote copy pairs are configured between the plurality of first logical disks and the plurality of second logical disks, to transmit data, received from a host computer for the plurality of first logical disks, from the plurality of first storage systems to the plurality of second storage systems by a synchronous remote copy procedure, and to write the data in the plurality of the second logical disks while keeping consistency of data in the plurality of second logical disks;

wherein a plurality of asynchronous type remote copy pairs are configured between the plurality of first logical disks and the plurality of third logical disks, to transmit data, received from a host computer for the plurality of first logical disks, from the plurality of first storage systems to the plurality of third storage systems by an asynchronous remote copy procedure, and to write the data in the plurality of the third logical disks while keeping consistency of data in the plurality of third logical disks;

wherein the copy group manager is configured to manage a synchronous copy group including the plurality of synchronous type remote copy pairs, and an asynchronous copy group including the plurality of asynchronous type remote copy pairs, to receive a report related to a failure of a remote copy process regarding one of the first logical disks from the plurality of first storage systems, to obtain information to specify one of the copy groups including one of the remote copy pairs related to the failure, and to decide whether the copy group, including the one of the remote copy pairs related to the failure, is the synchronous copy group or the asynchronous copy group, in order to suspend remote copy processes for the plurality of remote copy pairs included in the decided copy group,

wherein, in the plurality of first logical disks, one of the first logical disks in which data sent in accordance with an SCSI protocol is written, and another of the first logical disks in which data sent in accordance with a protocol other than the SCSI protocol is written, are included.

2. A remote copy system according to claim 1, wherein the report related to the failure of the remote copy process has information to specify the remote copy pair related to the failure, and the copy group including the remote copy pair related to the failure is specified based on the information included in the report.

3. A remote copy system according to claim 1, further comprising a step of:

if the remote copy pair related to the failure is included in the synchronous copy group, controlling to suspend remote copy processes for the plurality of synchronous type remote copy pairs, while keeping remote copy processes for the plurality of asynchronous type remote copy pairs.

4. A remote copy system according to claim 3, wherein the copy group manager is configured to suspend the remote copy processes by:

instructing the first controllers to pause write processes to the plurality of first logical disks, receiving completion reports of pausing the write processes from the first controllers, receiving the completion reports, instructing the first controllers to suspend remote copy processes for the plurality of synchronous remote copy pairs; and

instructing the first controllers to restart the write processes to the plurality of first logical disks after the remote copy processes for the plurality of synchronous remote copy pairs are suspended.

5. A remote copy system according to claim 4, wherein, when each first controller receives an instruction to pause the write processes to the plurality of first logical disks, the first controller is configured to execute a write process according to a write request received before the instruction, and to suspend a write process according to a write request received after the instruction.

6. A remote copy system according to claim 4, wherein the copy group manager is further configured to select the synchronous type copy group, to select the plurality of synchronous type remote copy pairs included in the synchronous copy group, and to instruct the first controllers to start the remote copy processes for the plurality of synchronous remote copy pairs.

7. A remote copy system according to claim 1,

wherein procedures to suspend remote copy processes are different between the plurality of synchronous type remote copy pairs and the plurality of asynchronous type remote copy pairs.

8. A remote copy method in a system, wherein:

the system comprises;

a plurality of first storage systems, including a plurality of first logical disks and first controllers;

a plurality of second storage systems, coupled to the plurality of first storage systems, including a plurality of second logical disks and second controllers; and

a plurality of third storage systems, coupled to the plurality of first storage systems, including a plurality of third logical disks and third controllers, the remote copy method comprising steps of;

configuring a plurality of synchronous type remote copy pairs, each including one of the plurality of first logical disks and one of the plurality of second logical disks, to transmit data, received by one of the plurality of first storage systems, including the one of the plurality of first logical disks, from a host computer, to one of the plurality of second storage systems by a synchronous remote copy procedure, and writing the data in the one of the plurality of second logical disks while keeping consistency of data in the plurality of second logical disks;

configuring a plurality of asynchronous type remote copy pairs, each including one of the plurality of first logical disks and one of the plurality of third logical disks, to transmit data, received by one of the plurality of first storage systems, including the one of the plurality of first logical disks, from a host computer, to one of the plurality of third storage systems by an asynchronous remote copy procedure, and writing the data in the one of the plurality of third logical disks while keeping consistency of data in the plurality of third logical disks;

creating a synchronous copy group, including the plurality of synchronous type remote copy pairs, and an asynchronous copy group, including the plurality of asynchronous type remote copy pairs;

sending data, received from a host computer, from one of the plurality of first storage systems to one of the plurality of second storage systems according to the plurality of synchronous type remote copy pairs and to one of the plurality of third storage systems according to the plurality of asynchronous type remote copy pairs;

storing the data received from the one of the plurality of first storage systems in one of the plurality of second logical disks according to the plurality of synchronous remote copy pairs;

storing the data received from one of the plurality of first storage systems in one of the plurality of third logical disks according to the plurality of asynchronous remote copy pairs;

receiving a report related to a failure of a remote copy process regarding one of the plurality of first logical disks;

obtaining information to specify one of the copy groups including the remote copy pair related to the failure; and

deciding whether the synchronous copy group or the asynchronous copy group includes the remote copy pair related to the failure, in order to suspend remote copy processes for the plurality of remote copy pairs included in the decided copy group while keeping consistency of data of a plurality of logical disks included in the plurality of remote copy pairs.

wherein, in the plurality of first logical disks, one of the first logical disks in which data sent in accordance with an SCSI protocol is written, and another one of the first logical disks in which data sent in accordance with a protocol other than the SCSI protocol is written, are included.

9. A remote copy method according to claim 8, wherein the report related to the failure of the remote copy process has information to specify the remote copy pair related to the failure, and the copy group including the remote copy pair related to the failure is specified based on the information included in the report.

10. A remote copy method according to claim 8, further comprising a step of:

if the remote copy pair related to the failure is included in the synchronous copy group, controlling to suspend remote copy processes for the plurality of synchronous type remote copy pairs, while continuing remote copy processes for the plurality of asynchronous type remote copy pairs.

11. A remote copy method according to claim 10, wherein the step of controlling to suspend the remote copy processes comprising steps of:

instructing the first controllers to pause write processes to the plurality of first logical disks;

receiving completion reports of pausing the write processes from the first controllers;

after receiving the completion reports, instructing the first controllers to suspend remote copy processes for the plurality of synchronous remote copy pairs; and

instructing the first controllers to restart the write processes to the plurality of first logical disks after the remote copy processes for the plurality of synchronous remote copy pairs are suspended.

12. A remote copy method according to claim 11, wherein, when each first controller receives an instruction to pause the write processes to the plurality of first logical disks, the first controller executes a write process according to a write request received before the instruction, and suspends a write process according to a write request received after the instruction.

13. A remote copy method according to claim 11, further comprising steps of:

selecting the synchronous type copy group;

selecting the plurality of synchronous type remote copy pairs included in the synchronous copy group; and

instructing the first controllers to start the remote copy processes for the plurality of synchronous remote copy pairs.

14. A remote copy method according to claim 8,

wherein procedures to suspend remote copy processes are different between the plurality of synchronous type remote copy pairs and the plurality of asynchronous type remote copy pairs.