Database recovery method applying update journal and database log

• US 20070185923A1
• Filed: 03/23/2006
• Published: 08/09/2007
• Est. Priority Date: 01/27/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Mogi, Kazuhiko, Oeda, Takashi, Nishikawa, Norifumi, Kawamura, Nobuo
• Granted Patent: US 7,472,139 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• 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 707/99945 Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A database recovery method including a computer and a storage system, in which: the storage system includes a disk drive for storing data; the disk drive includes a data volume, a snapshot volume, a database log for storing an update log, and an update journal for storing update information of the data volume; a recovery point for indicating an end point of a range to which the update journal is to be applied and a starting point of a range to which the database log is to be applied is recorded to recover the data volume; and when the database is to be recovered, the update journal is applied to the snapshot volume up to the recovery point, the snapshot volume after the update is switched to the data volume, and the database log after the recovery point is applied to the data volume that is set by switching.

Claims

1. A database recovery method for a computer system,

the computer system comprising:

a computer having a database management system; and

a storage system for storing data accessed from the computer,

the computer comprising;

a port connected to the storage system;

a processor connected to the port; and

a memory connected to the processor,

the storage system comprising;

a port connected to the computer;

a control unit connected to the port and including a processor and a memory; and

a disk drive for storing data which is a target of a write request issued by the computer,

the disk drive including;

a data volume for storing the data;

a snapshot volume corresponding to a copy of the data volume;

a database log for storing an update log of the data; and

an update journal for storing update information of the data volume,

the database management system recording a recovery point for indicating an end point of a range to which the update journal is to be applied and a starting point of a range to which the database log is to be applied when the data volume is damaged,

the database recovery method comprising;

applying the update journal to the snapshot volume up to the recovery point;

switching the updated snapshot volume to the data volume; and

applying the database log after the recovery point to the data volume that is set by switching.

2. The database recovery method according to claim 1, wherein the update information includes a data image of the updated data volume.

3. The database recovery method according to claim 1, wherein the applying of the update journal is executed by the storage system.

4. The database recovery method according to claim 1, wherein the recovery point includes a relation between the database log and the update information.

5. The database recovery method according to claim 1, wherein:

the database management system temporarily accumulates the updated data, sets a checkpoint for collectively recording the accumulated update data at a predetermined time in the data volume, and records the recovery point upon setting of the latest checkpoint.

6. The database recovery method according to claim 5, wherein:

the checkpoint is recorded in the database log; and

the recovery point includes a relation between the checkpoint recorded in the database log and the latest update information of the update journal.

7. A computer system, comprising:

a computer having a database management system; and

a storage system for storing data accessed from the computer, wherein;

the computer comprises a port connected to the storage system, a processor connected to the port and a memory connected to the processor;

the storage system comprises a port connected to the computer, a control unit connected to the port and including a processor and a memory and a disk drive for storing data which is a target of a write request issued by the computer;

the disk drive includes a data volume for storing the data, a snapshot volume corresponding to a copy of the data volume, a database log for storing an update log of the data and an update journal for storing update information of the data volume; and

the database management system

records a recovery point for indicating an end point of a range to which the update journal is to be applied and a starting point of a range to which the database log is to be applied when the data volume is damaged during a normal operation of the computer system,

applies the update journal to the snapshot volume up to the recovery point when an error occurs in the data volume,

switches the updated snapshot volume to the data volume, and

applies the database log after the recovery point to the data volume that is set by switching.

8. The computer system according to claim 7, wherein the update information includes a data image of the updated data volume.

9. The computer system according to claim 7, wherein the storage system applies the update journal.

10. The computer system according to claim 7, wherein the recovery point includes a relation between the database log and the update information.

11. The computer system according to claim 7, wherein the database management system temporarily accumulates the updated data, collectively records the accumulated update data at a predetermined time in the data volume, and records the recovery point upon setting of the latest checkpoint.

12. The computer system according to claim 11, wherein:

the checkpoint is recorded in the database log; and

the recovery point includes a relation between the checkpoint recorded in the database log and the latest update information of the update journal.