Remote copying system with consistency guaranteed between a pair

• US 8,161,009 B2
• Filed: 02/02/2006
• Issued: 04/17/2012
• Est. Priority Date: 04/23/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Iwamura, Takashige, Takahashi, Masamitsu, Satoh, Takao, Maki, Nobuhiro
• Primary Examiner(s): Radtke, Mark Andrew X
• Application Number:
  US11/345,544
• Publication Number:
  US 20060161721A1
• Time in Patent Office: 2,266 Days
• Field of Search: 707/658
• US Class Current: 707/658
• 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 method for controlling a remote copy system, wherein the remote copy system includes:

a first system coupled to a host computer, wherein the first system includes a plurality of first logical disks, to which data is written from the host computer while keeping the data consistent;

a second system coupled to the first system, wherein the second system includes a plurality of second logical disks, wherein a plurality of synchronous type remote copy pairs are configured, each of which includes one of the plurality of first logical disks and one of the plurality of second logical disks, in accordance with a synchronous remote copy operation to transfer data from the first system to the second system, and wherein data transmitted from the first system to the second system is written in the plurality of second logical disks while keeping the data consistent, and

a third system coupled to the first system, wherein the third system includes a plurality of third logical disks, wherein a plurality of asynchronous type remote copy pairs are configured, each of which includes one of the plurality of first logical disks and one of the plurality of third logical disks, in accordance with an asynchronous copy operation to transfer data from the first system to the third system, and wherein data transmitted from the first system to the third system is written in the plurality of third logical disks while keeping the data consistent,

wherein 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 are configured,

the method comprising steps of;

receiving a report related to a failure of a remote copy process regarding to a first logical disk;

obtaining information to specify a copy group including a remote copy pair including the first logical disk related to the failure; and

deciding whether the synchronous copy group or the asynchronous copy group includes the remote copy pair including the first logical disk related to the failure,

suspending a remote copy process regarding the synchronous copy group or the asynchronous copy group related to the failure while keeping the data consistent of a plurality of logical disks included in a plurality of remote copy pairs in the synchronous copy group or the asynchronous copy group related to the failure; and

continuing a remote copy process regarding the other of the synchronous or asynchronous copy group for which failure is not detected, after suspension of the remote copy process regarding the synchronous copy group or the asynchronous copy group related to the failure,

wherein, before the failure of the remote copy process regarding the first logical disk, data written by the host computer is transferred to the second system by the synchronous remote copy operation, and also transferred to the third system by the asynchronous remote copy operation, and

wherein the transferred data by the asynchronous remote copy operation from the first system to the third system is not passed in the second system, during the synchronous remote copy operation from the first system to the second system being performed.

2. A method for controlling a remote copy system according to claim 1, wherein in each of the plurality of synchronous remote copy pairs, data received from the host computer is transmitted from the first system to the second system and stored in one of the plurality of second logical disks synchronously with a write request from the host computer.

3. A method for controlling a remote copy system according to claim 1, wherein in each of the plurality of asynchronous remote copy pairs, data received from the host computer is transmitted from the first system to the third system and stored in one of the plurality of third logical disks asynchronously with a write request from the host computer.

4. A method for controlling a remote copy system according to claim 3, wherein in the plurality of asynchronous remote copy pairs, data received from the host computer and management information relating to write order of the data are transmitted from the first system to the third system, and wherein data received at the third system is stored in the plurality of third logical disks in same order as the write order according to the management information.

5. A method for controlling a remote copy system according to claim 3, wherein in the plurality of asynchronous remote copy pairs, data received from the host computer is kept in the first system during a period, and wherein

after expiring the period, the data kept in the first system is transmitted to the third system and copied in the plurality of third logical disks.

6. A method for controlling 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 including the first logical disk related to the failure, and the copy group including the remote copy pair including the first logical disk related to the failure is specified based on the information included in the report.

7. A method for controlling a remote copy system according to claim 1,

wherein procedure to suspend a remote copy process is different between a synchronous type remote copy pair and an asynchronous type remote copy pair.

8. A method for controlling a remote copy system according to claim 1, further comprising a step of:

if the remote copy pair including the first logical disk 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, with keeping remote copy processes for the plurality of asynchronous type remote copy pairs.

9. A method for controlling a remote copy system according to claim 8, wherein the step of controlling to suspend a remote copy processes comprising steps of:

instructing a first control device coupled to a first logical disk included in the plurality of synchronous type remote copy pairs, to pause a write process to the first logical disk;

receiving a completion report of pausing a write process from the first control device;

after receiving the completion report, instructing the first control device to suspend a remote copy process for a synchronous remote copy pair including the first logical disk; and

instructing the first control device to restart the write process to the first logical disk.

10. A method for controlling a remote copy system according to claim 9, wherein when the first control device receives an instruction to pause the write process to the first logical disk, the first control device 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.

11. A method for controlling a remote copy system according to claim 8, 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 a first control device coupled to a first logical disk included in the selected plurality of synchronous type remote copy pairs to start the remote copy processes for the selected synchronous remote copy pairs.

12. A method for controlling a remote copy system according to claim 1, wherein the first system includes a plurality of first storage systems each of which has a first control device and at least one first logical disk coupled to the first control device, the second system includes a plurality of second storage systems each of which has a second control device and at least one second logical disk coupled to the second control device, and the third system includes a plurality of third storage systems each of which has a third control device and at least one third logical disk.

13. A remote copy system comprising:

a copy group manager;

a first system including a plurality of first logical disks, wherein the first system is configured to write data received from a host computer to the plurality of first logical disks while keeping the data consistent;

a second system including a plurality of second logical disks; and

a third system including a plurality of third logical disks;

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 in accordance with a synchronous remote copy operation to transfer data from the first system to the second system, and data transmitted from the first system to the second system is written in the plurality of second logical disks while keeping the data consistent,

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 in accordance with an asynchronous copy operation to transfer data from the first system to the third system, and data transmitted from the first system to the third system is written in the plurality of third logical disks while keeping the data consistent,

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, receive a report related to a failure of a remote copy process regarding to a first logical disk from the first system;

obtain information to specify a copy group including a remote copy pair including the first logical disk related to the failure;

decide whether a copy group including a remote copy pair including the first logical disk related to the failure is the synchronous copy group or the asynchronous copy group;

suspend a remote copy process regarding the synchronous copy group or the asynchronous copy group related to the failure while keeping the data consistent of a plurality of logical disks included in a plurality of remote copy pairs in the synchronous copy group or the asynchronous copy group related to the failure; and

continue a remote copy process regarding the other of the synchronous or asynchronous copy group for which failure is not detected, after suspension of the remote copy process regarding the synchronous copy group or the asynchronous copy group related to the failure,

wherein, before the failure of the remote copy process regarding the first logical disk, data written by the host computer is transferred to the second system by the synchronous remote copy operation, and also transferred to the third system by the asynchronous remote copy operation, and

wherein the transferred data by the asynchronous remote copy operation from the first system to the third system is not passed in the second system, during the synchronous remote copy operation from the first system to the second system being performed.

14. A remote copy system according to claim 13, wherein for each of the plurality of synchronous remote copy pairs, the first system is configured to transmit data received from the host computer to the second system synchronously with a write request from the host computer, and the second system is configured to store the data in one of the plurality of second logical disks.

15. A remote copy system according to claim 13, wherein for each of the plurality of asynchronous remote copy pairs, the first system is configured to transmit data received from the host computer to the third system asynchronously with a write request from the host computer, and the third system is configured to store the data in one of the plurality of third logical disks.

16. A remote copy system according to claim 15, wherein for the plurality of asynchronous remote copy pairs, the first system is configured to transmit data received from the host computer and management information relating to write order of the data to the third system, and the third system is configured to store the data received from the first system in the plurality of third logical disks in same order as the write order according to the management information.

17. A remote copy system according to claim 15, wherein for the plurality of asynchronous remote copy pairs, the first system is configured to keep data received from the host computer during a period, and after expiring the period, the first system is configured to transmit the kept data to the third system, and

wherein the third system is configured to store the data received from the first system in the plurality of third logical disks.

18. A remote copy system according to claim 13, wherein the report related to the failure of the remote copy process includes information to specify the remote copy pair including the first logical disk related to the failure, and the copy group manager is configured to decides the copy group including the remote copy pair including the first logical disk related to the failure based on the information in the report.

19. A remote copy system according to claim 13, wherein a procedure to suspend a remote copy process is different between a synchronous remote copy pair and an asynchronous remote copy pair.

20. A remote copy system according to claim 13, wherein, if the remote copy pair including the first logical disk related to the failure is included in the synchronous copy group, the copy group manager is configured to control to suspend remote copy processes for the plurality of synchronous type remote copy pairs with keeping remote copy processes for the plurality of asynchronous type remote copy pairs.

21. A remote copy system according to claim 20, wherein if the remote copy pair including the first logical disk related to the failure is included in the synchronous copy group, the copy manger is configured to instruct a first control device coupled to a first logical disk included in the plurality of synchronous type remote copy pairs, to pause a write process to the first logical disk, receive a completion report of pausing a write process from the first control device, after receiving the completion report, instruct the first control device to suspend the remote copy process for a synchronous remote copy pair including the first logical disk, and instruct the first control device to restart the write process to the first logical disk.

22. A remote copy system according to claim 21, wherein when the first control device receives an instruction to pause the write process to the first logical disk from the copy manager, the first control device is configured to execute a write process according to a write request received before the instruction, and suspend a write process according to a write request received after the instruction.

23. A remote copy system according to claim 20, wherein, in order to restart the suspended remote copy processes for the plurality of synchronous type remote copy pairs, the copy manager is configured to select the synchronous copy group, select the plurality of synchronous type remote copy pairs included in the synchronous copy group, and instruct a first control device coupled to a first logical disk included in the plurality of synchronous type remote copy pairs to start the remote copy processes for the selected synchronous remote copy pairs.

24. A remote copy system according to claim 13,

wherein the first system includes a plurality of first storage systems, each of which has a first control device and at least one first logical disk coupled to the first control device, the second system includes a plurality of second storage systems, each of which has a second control device and at least one second logical disk coupled to the second control device, and the third system includes a plurality of third storage systems, each of which has a third control device and at leas one third logical disk.

25. A remote copy system according to claim 13,

wherein the copy group manager includes a pair information showing a type of each remote copy pair and copy group information showing relation between a copy group and a remote copy pair included in the corresponding copy group, and

wherein the copy group manager is configured to configure a copy group including a plurality of same type remote copy pairs.

26. A computer program product for controlling a remote copy system, wherein the remote copy system includes:

a first system coupled to a host computer, wherein the first system includes a plurality of first logical disks, to which data is written from the host computer while keeping the data consistent;

a second system coupled to the first system, wherein the second system includes a plurality of second logical disks are configured, wherein a plurality of synchronous type remote copy pairs, each of which includes one of the plurality of first logical disks and one of the plurality of second logical disks, in accordance with a synchronous remote copy operation to transfer data from the first system to the second system, and wherein data transmitted from the first system to the second system is written in the plurality of second logical disks while keeping the data consistent, and

a third system coupled to the first system, wherein the third system includes a plurality of third logical disks are configured, wherein a plurality of asynchronous type remote copy pairs, each of which includes one of the plurality of first logical disks and one of the plurality of third logical disks, in accordance with an asynchronous copy operation to transfer data from the first system to the third system, and wherein data transmitted from the first system to the third system is written in the plurality of third logical disks while keeping the data consistent, and

wherein 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 are configured,

the computer program product comprising;

a recording medium;

a failure report receiving section, recorded on the recording medium, that receives a report related to a failure of a remote copy process regarding to a first logical disk;

an information obtaining section, recorded on the recording medium, that obtains information to specify a copy group including a remote copy pair including the first logical disk related to the failure; and

a deciding section, recorded on the recording medium, that decides whether the synchronous copy group or the asynchronous copy group includes the remote copy pair including the first logical disk related to the failure, suspends a remote copy process regarding the synchronous copy group or the asynchronous copy group related to the failure while keeping the data consistent of a plurality of logical disks included in a plurality of remote copy pairs in the synchronous copy group or the asynchronous copy group related to the failure, and continues a remote copy process regarding the other of the synchronous or asynchronous copy group for which failure is not detected, after suspension of the remote copy process regarding the synchronous copy group or the asynchronous copy group related to the failure,

wherein, before the failure of the remote copy process regarding the first logical disk, data written by the host computer is transferred to the second system by the synchronous remote copy operation, and also transferred to the third system by the asynchronous remote copy operation, and

wherein the transferred data by the asynchronous remote copy operation from the first system to the third system is not passed in the second system, during the synchronous remote copy operation from the first system to the second system being performed.

27. A computer program product according to claim 26, further comprising:

copy group information, recorded on the recording medium, that shows relation between a copy group and a remote copy pair included in the corresponding copy group, and wherein

the deciding section decides whether the synchronous copy group or the asynchronous copy group includes the remote copy pair including the first logical disk related to the failure based on the copy group information.

28. A computer program product according to claim 27, further comprising a controlling section, recorded in the recording medium, that controls to suspend remote copy processes for the plurality of synchronous type remote copy pairs, with keeping remote copy processes for the plurality of asynchronous type remote copy pairs, if the remote copy pair including the first logical disk related to the failure is included in the synchronous copy group.

29. A computer program product according to claim 28, wherein the controlling section includes:

a write pause instructing section that instructs a first control device coupled to a first logical disk included in the plurality of synchronous type remote copy pairs, to pause a write process to the first logical disk;

a completion report receiving section that receives a completion report of pausing a write process from the first control device;

a suspend instructing section that instructs the first control device to suspend a remote copy process for a synchronous remote copy pair including the first logical disk after receiving the completion report; and

a restart instructing section that instructs the first control device to restart the write process to the first logical disk.

30. A computer program product according to claim 28, further comprising:

a copy group selecting section, recorded in the recording medium, that selects the synchronous type copy group;

a remote copy pair selecting section, recorded in the recording medium, that selects the plurality of synchronous type remote copy pairs included in the synchronous copy group; and

a remote copy restart instructing section, recorded in the recording medium, that instruct a first control device coupled to a first logical disk included in the selected plurality of synchronous type remote copy pairs to start the remote copy processes for the selected synchronous remote copy pairs.