System and method for adding a standby computer into clustered computer system

• US 20090172142A1
• Filed: 02/26/2008
• Published: 07/02/2009
• Est. Priority Date: 12/27/2007
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hara, Norihiro, Baba, Tsunehiko, Hanai, Tomohiro
• Granted Patent: US 8,195,777 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: G06F 15/16 Combinations of two or more digital computers each having at least an arithmetic unit, a program unit and a register, e.g. for a simultaneous processing of several programs coordinating program control therefor G06F9/52; in regulating and control system G05B

Abstract

There is provided a method of adding a new computer as a standby computer to a computer system that includes an active computer for performing service processing and a standby computer for storing replica of data stored in the active computer. The replica of the data stored in the standby computer is updated when the data stored in the active computer is updated. The method comprising the steps of: selecting the standby computer from the computer system; transferring the replica of the data stored in the selected standby computer to the new computer; and transferring update information on data updated in the active computer after the transferring the replica of the data is started, to the new computer.

Claims

1. A method of adding a new computer as a standby computer to a computer system that includes an active computer for performing service processing and a standby computer for storing replica of data stored in the active computer,

the replica of the data stored in the standby computer is updated when the data stored in the active computer is updated,

the method comprising the steps of:

selecting the standby computer from the computer system;

transferring the replica of the data stored in the selected standby computer to the new computer; and

transferring update information on data updated in the active computer after the transferring the replica of the data is started, to the new computer.

2. The method according to claim 1, wherein:

the active computer comprises a database management system operated therein and the data stored in the active computer is managed by the database management system; and

the standby computer each comprise a database management system operated therein; and

the replica of the data stored in the standby computer is managed by the database management system.

3. The method according to claim 2, wherein the update information includes an update log generated by the database management system.

4. The method according to claim 1, further comprising the step of temporarily stopping processing of applying the update information on the data stored in the active computer to the replica of the data stored in the selected standby computer before the selected standby computer transfers the replica of the data to the new computer.

5. The method according to claim 4, further comprising the step of restarting the processing of applying the update information on the data stored in the active computer to the replica of the data stored in the selected standby computer after the selected standby computer transfers the replica of the data to the new computer.

6. The method according to claim 4, further comprising the step of the applying the update information transferred to a new computer after the transferring the replica of the data is started until the transferring the replica of the data is completed, to the replica of the data stored in the new computer after the selected standby computer transfers the replica of the data to the new computer.

7. The method according to claim 6, wherein, in the step of the applying the update information, the update information is applied only to replica of the data to which the update information has not been applied yet.

8. The method according to claim 6, further comprising the step of transferring the update information from the selected standby computer.

9. The method according to claim 1, wherein, in the step of selecting the standby computer, the standby computer which transfers the replica of the data stored in the active computer is selected in accordance with resource usage of the standby computer included in the computer system.

10. The method according to claim 9, wherein, in the step of selecting the standby computer, the usage of a resource of at least one of a processor, a memory and a network is used as the resource usage.

11. The method according to claim 1, wherein:

the computer system further includes a storage device which stores data; and

the method further comprises the step of determining whether the storage device is used to transfer the replica of the data to the new computer in accordance with resource usage of the selected standby computer.

12. The method according to claim 1, wherein:

the computer system provides logical computers by logically partitioning a physical resource of the active computer and the standby computer; and

the method further comprises the step of starting the transferring the replica of the data, after resource usage by the logical computer is changed, in the case of which at least one of the selected standby computer and the new computer is the logical computer.

13. A standby computer which is included in a computer system that includes an active computer for performing service processing and the standby computer for storing replica of data stored in the active computer, wherein:

an update information is applied to the replica of the data stored in the standby computer in the case of which the data stored in the active computer is updated; and

the standby computer is, for adding a new computer as another standby computer to the computer system, configured to;

temporarily stop processing of applying the update information on the data stored in the active computer to the replica of the data stored in the standby computer in the case of which a transmission request of the replica of the data is transmitted from the new computer; and

transfer the replica of the data stored in the standby computer to the new computer.

14. The computer according to claim 13, wherein the computer is configured to restart applying the update information on the data stored in the active computer to the replica of the data stored in the computer after the transfer of the replica of the data to the new computer is completed.

15. A computer system comprising an active computer for performing service processing and a standby computer for storing replica of data stored in the active computer, wherein:

an update information is applied to the replica of the data stored in the standby computer in the case of which the data stored in the active computer is updated;

a new computer selects the standby computer from the computer system in the case of which the new computer is added as another standby computer to the computer system,

the selected standby computer transfers the replica of the data to the new computer, and

one of the active computer and the standby computer transfers the update information on data updated in the active computer after the transfer of the replica of the data from the selected standby computer to the new computer is started, to the new computer.

16. The computer system according to claim 15, wherein:

the active computer comprise a database management system operated therein, and the data stored in the active computer is managed by the database management system;

the standby computer each comprise a database management system operated therein, the replica of the data stored in the standby computer is managed by the database management system; and

the update information includes an update log generated by the database management system.

17. The computer system according to claim 15, wherein the new computer stores the replica of the data transferred from the selected standby computer and requests one of the active computer and the standby computer to transmit update information on data updated in the active computer after the transfer of the replica of the data is started until the storage of the transferred replica of the data is completed.