BACKUP APPARATUS, BACKUP METHOD AND BACKUP PROGRAM

• US 20100138622A1
• Filed: 11/19/2009
• Published: 06/03/2010
• Est. Priority Date: 12/03/2008
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: FURUYA, Masanori
• Granted Patent: US 8,402,235 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

A backup apparatus has an address conversion table for storing, in correspondence with each other, a logical address and a physical address. The backup apparatus has a sequential data count setting unit, a sequential data information acquisition unit, and a reading unit. The sequential data count setting unit sets sequential data count information indicating the number of data blocks in a sequence in the physical address in the address conversion table. The sequential data information acquisition unit, upon receiving a read request, reads the data block in the address conversion table corresponding to the leading logical address among the logical addresses requested to be read and acquires the sequential data count information set in the address conversion table. The reading unit reads a physical volume corresponding to physical addresses in a sequence in accordance with the sequential data count information acquired by the sequential data information acquisition unit.

Claims

1. A backup apparatus having an address conversion table for storing, in correspondence with each other, a logical address designated by a host system and a physical address indicating a data storage position in a copy destination volume, the backup apparatus comprising:

a sequential data count setting unit for setting sequential data count information indicating the number of data blocks in a sequence in the physical address in the address conversion table;

a sequential data information acquisition unit which, upon receiving a read request, reads the data block in the address conversion table corresponding to the leading logical address among the logical addresses requested to be read, and acquires the sequential data count information set in the address conversion table; and

a reading unit for reading a physical volume corresponding to the physical addresses in a sequence in accordance with the sequential data count information acquired by the sequential data information acquisition unit.

2. The backup apparatus according to claim 1, wherein the sequential data count setting unit determines whether the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence or not, and if the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence, the sequential data count information is set as a sequence of the physical address corresponding to the last assigned logical address to the address conversion table and the physical address corresponding to the logical address presently assigned to the address conversion table.

3. The backup apparatus according to claim 1, further comprising a sequential data count update unit which, if no new assignment of the address conversion table occurs within a certain time, determines whether the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence or not, and if the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence, updates the sequential data count information as a sequence of the physical address corresponding to the last assigned logical address to the address conversion table and the physical address corresponding to the logical address presently assigned to the address conversion table.

4. The backup apparatus according to claim 1, wherein,

when a request is received to read a logical address whose sequential data count information to be set by the sequential data count setting unit is not yet set, the reading unit reads a physical volume that is a sequence of physical addresses up to the physical address last assigned to the address conversion table.

5. A backup method using an address conversion table for storing, in correspondence with each other, a logical address designated by a host system and a physical address indicating a data storage position in a copy destination volume, the method comprising:

setting sequential data count information indicating the number of data blocks in a sequence in the physical address;

reading the data block, upon receiving a read request, in the address conversion table corresponding to a leading logical address among the logical addresses requested to be read, and acquiring the sequential data count information set in the address conversion table; and

reading a physical volume corresponding to the physical addresses in a sequence in accordance with the sequential data count information acquired.

6. The method according to claim 5, further comprising:

determining whether a last assigned logical address to the address conversion table and a logical address presently assigned to the address conversion table make up a sequence or not, and

if the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table are make up a sequence, setting the sequential data count information as a sequence of the physical address corresponding to the last assigned logical address to the address conversion table and the physical address corresponding to the logical address presently assigned to the address conversion table.

7. The method according to claim 5, further comprising,

if no new assignment of the address conversion table occurs within a certain time, determining whether the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence or not, and

if the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence, updating the sequential data count information as a sequence of the physical address corresponding to the last assigned logical address to the address conversion table and the physical address corresponding to the logical address presently assigned to the address conversion table.

8. The method according to claim 5, comprising,

when a request to read a logical address whose sequential data count information to be set in the sequential data count setting is not yet set is received, reading a physical volume that is a sequence of physical addresses up to the physical address last assigned to the address conversion table.

9. A computer-readable recording medium encoded with a backup program using an address conversion table for storing, in correspondence with each other, a logical address designated by a host system and a physical address indicating a data storage position in a copy destination volume, and containing instructions executable on a computer, the program causing the computer to execute:

setting, in the address conversion table, sequential data count information indicating the number of the data blocks in a sequence in the physical address;

reading the data block, upon receiving a read request, in the address conversion table corresponding to a leading logical address among the logical addresses requested to be read, and acquiring the sequential data count information set in the address conversion table; and

reading a physical volume corresponding to physical addresses in a sequence in accordance with the sequential data count information acquired.

10. The computer-readable recording medium according to claim 9, further comprising determining whether a last assigned logical address to the address conversion table and a logical address presently assigned to the address conversion table make up a sequence or not, and if the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence, the sequential data count information is set as a sequence of the physical address corresponding to the last assigned logical address to the address conversion table and the physical address corresponding to the logical address presently assigned to the address conversion table.

11. The computer-readable recording medium according to claim 9, further comprising, if no new assignment of the address conversion table occurs within a certain time, determining whether the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence or not, and if the last assigned logical address to the address conversion table and the logical address presently assigned to the address conversion table make up a sequence, updating the sequential data count information as a sequence of the physical address corresponding to the last assigned logical address to the address conversion table and the physical address corresponding to the logical address presently assigned to the address conversion table.

12. The computer-readable recording medium according to claim 9, comprising, when a request to read a logical address whose sequential data count information to be set in the sequential data count setting is not yet set is received, reading a physical volume that is a sequence of physical addresses up to the physical address last assigned to the address conversion table.