Apparatus and storage system for controlling acquisition of snapshot

• US 7,017,076 B2
• Filed: 02/02/2004
• Issued: 03/21/2006
• Est. Priority Date: 07/29/2003
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tabuchi, Hideo, Ohno, Hiroshi, Shimada, Akinobu, Innan, Masataka
• Primary Examiner(s): Beausoliel, Robert
• Assistant Examiner(s): Duncan, Marc
• Application Number:
  US10/768,173
• Publication Number:
  US 20050027749A1
• Time in Patent Office: 778 Days
• Field of Search: 714/16, 714/15, 714/19, 714/20, 714/21, 714/54, 707/202, 707/204
• US Class Current: 714/15
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 16/2308 Concurrency control transaction processing G06F9/466
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 2201/80 Database-specific techniques
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A DBMS performs a checkpoint process for maintaining consistency of data. A snapshot acquisition control program detects the checkpoint process externally to the DBMS and creates a snapshot in an external storage according to the timing of the checkpoint. Correspondence between checkpoints and snapshots is maintained in a CP-SH correspondence management table to make it possible to restore in a short time data at the time of an arbitrary checkpoint.

Claims

1. A snapshot acquisition software stored in a computer readable medium for controlling acquisition of a snapshot cooperating with a computer system having a host computer on which a database management program (hereinafter referred to as DBMS) is operating, an external storage which is external to the host computer and the snapshot acquisition controller and which stores data managed by said DBMS, and a snapshot function unit for acquiring a snapshot of data on said external storage upon receipt of a snapshot acquisition request, said DBMS intermittently executing a checkpoint process for temporarily storing update data for updating data on said external storage in a buffer and outputting all update data accumulated in said buffer to said external storage according to timing controlled by said DBMS, comprising:

a checkpoint detection module which detects the execution of said checkpoint process that said DBMS intermittently executes according to timing controlled by said DBMS; and

a snapshot acquisition request module which transmits said snapshot acquisition request to said snapshot function unit when the execution of said checkpoint is detected by said checkpoint detection module,

wherein said checkpoint detection module detects the execution of said checkpoint process by monitoring an operation log that is a record of history of operations including said checkpoint process executed by said DBMS.

2. A snapshot acquisition software according to claim 1, wherein said snapshot acquisition request is transmitted without requesting said DBMS to staticize a database or to staticize a virtual database.

3. A snapshot acquisition software according to claim 1, wherein further comprising identification information storing module which stores checkpoint identification information for identifying a detected checkpoint process and snapshot identification information for identifying an acquired snapshot in association with each other when said snapshot is acquired as a result of detection of the execution of said checkpoint process.

4. A snapshot acquisition software according to claim 3, wherein further comprising a snapshot restoration instructing module which, upon receipt of a snapshot recovery instruction including the specification of arbitrary checkpoint identification information, acquires snapshot identification information stored in association with the specified checkpoint identification information from said identification information storing module and which transmits a restoration request for a snapshot identified by the acquired snapshot identification information to said snapshot function unit or a predetermined functional unit having a snapshot restoring function.

5. A snapshot acquisition software according to claim 1, wherein when said DBMS executes said checkpoint process at a first time interval, said checkpoint detection module performs a monitoring operation for detecting said checkpoint process at a second time interval shorter than said first time interval.

6. A snapshot acquisition software software stored in a computer readable medium for controlling acquisition of a snapshot cooperating with a computer system having a host computer on which a database management program (hereinafter referred to as DBMS) is operating, an external storage which is external to the host computer and the snapshot acquisition controller and which stores data managed by said DBMS, and a snapshot function unit for acquiring a snapshot of data on said external storage upon receipt of a snapshot acquisition request, said DBMS intermittently executing a checkpoint process for temporarily storing update data for updating data on said external storage in a buffer and outputting all update data accumulated in said buffer to said external storage according to timing controlled by said DBMS, comprising:

a checkpoint detection module which detects the execution of said checkpoint process that said DBMS intermittently executes according to timing controlled by said DBMS; and

a snapshot acquisition request module which transmits said snapshot acquisition request to said snapshot function unit when the execution of said checkpoint is detected by said checkpoint detection module,

wherein when said DBMS has a user interface for a manager and outputs information regarding said checkpoint process to said user interface for a manager, said checkpoint detection module detects the execution of said checkpoint process by monitoring information output by said DBMS to said user interface for a manager.

7. A snapshot acquisition software according to claim 6, wherein when said DBMS executes said checkpoint process at a first time interval, said checkpoint detection module performs a monitoring operation for detecting said checkpoint process at a second time interval shorter than said first time interval.

8. A snapshot acquisition software according to claim 6, wherein said snapshot acquisition request is transmitted without requesting said DBMS to staticize a database or to staticize a virtual database.

9. A snapshot acquisition software according to claim 6, further comprising:

identification information storing module which stores checkpoint identification information for identifying a detected checkpoint process and snapshot identification information for identifying an acquired snapshot in association with each other when said snapshot is acquired as a result of detection of the execution of said checkpoint process.

10. A snapshot acquisition software according to claim 9, further comprising:

a snapshot restoration instructing module which, upon receipt of a snapshot recovery instruction including the specification of arbitrary checkpoint identification information, acquires snapshot identification information stored in association with the specified checkpoint identification information from said identification information storing module and which transmits a restoration request for a snapshot identified by the acquired snapshot identification information to said snapshot function unit or a predetermined functional unit having a snapshot restoring function.

11. A snapshot acquisition software stored in a computer readable medium for controlling acquisition of a snapshot cooperating with a computer system having a host computer on which a database management program (hereinafter referred to as DBMS) is operating, an external storage which is external to the host computer and the snapshot acquisition controller and which stores data managed by said DBMS, and a snapshot function unit for acquiring a snapshot of data on said external storage upon receipt of a snapshot acquisition request, said DBMS intermittently executing a checkpoint process for temporarily storing update data for updating data on said external storage in a buffer and outputting all update data accumulated in said buffer to said external storage according to timing controlled by said DBMS, comprising:

a checkpoint detection module which detects the execution of said checkpoint process that said DBMS intermittently executes according to timing controlled by said DBMS; and

a snapshot acquisition request module which transmits said snapshot acquisition request to said snapshot function unit when the execution of said checkpoint is detected by said checkpoint detection module,

wherein when said DBMS executes said checkpoint process at a first time interval, said checkpoint detection module performs a monitoring operation for detecting said checkpoint process at a second time interval shorter than said first time interval.

12. A snapshot acquisition software according to claim 11, wherein said snapshot acquisition request is transmitted without requesting said DBMS to staticize a database or to staticize a virtual database.

13. A snapshot acquisition software according to claim 11, further comprising:

identification information storing module which stores checkpoint identification information for identifying a detected checkpoint process and snapshot identification information for identifying an acquired snapshot in association with each other when said snapshot is acquired as a result of detection of the execution of said checkpoint process.

14. A snapshot acquisition software according to claim 13, further comprising:

a snapshot restoration instructing module which, upon receipt of a snapshot recovery instruction including the specification of arbitrary checkpoint identification information, acquires snapshot identification information stored in association with the specified checkpoint identification information from said identification information storing module and which transmits a restoration request for a snapshot identified by the acquired snapshot identification information to said snapshot function unit or a predetermined functional unit having a snapshot restoring function.

15. A storage system used in conjunction with a host computer on which a DBMS operates, comprising:

an external storage which is external to the host computer and the snapshot acquisition controller and which stores data in a database managed by said DBMS;

a snapshot function unit which acquires a snapshot of data on said external storage upon receipt of a snapshot acquisition request; and

a snapshot acquisition control unit for controlling the acquisition of said snapshot and in that when said DBMS is adapted to temporarily store update data for updating the data on said external storage in a buffer and to intermittently execute a checkpoint process for outputting all update data accumulated in said buffer to said external storage at timing controlled by said DBMS, said snapshot acquisition control unit has;

checkpoint detecting means which detects the execution of said checkpoint process that the DBMS intermittently executes at timing controlled by said DBMS; and

snapshot acquisition requesting means which transmits said snapshot acquisition request to said snapshot function means when the execution of said checkpoint is detected by said checkpoint detection means,

wherein said checkpoint detection means detects the execution of said checkpoint process by monitoring an operation log that is a record of history of operations including said checkpoint process executed by said DBMS.

16. A snapshot storage system according to claim 15, wherein when said DBMS executes said checkpoint process at a first time interval, said checkpoint detection means performs a monitoring operation for detecting said checkpoint process at a second time interval shorter than said first time interval.