Backup method, storage system, and program for backup

• US 20050216535A1
• Filed: 07/26/2004
• Published: 09/29/2005
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Saika, Nobuyuki, Fujii, Naohiro
• Granted Patent: US 7,287,045 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• 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
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A backup method is provided for use with a storage system composed of a memory which stores a control program, a disk drive having an primary volume, a differential volume, and mapping information, the primary volume storing data sent from a client, the differential volume storing differential data of a snapshot of the primary volume, the mapping information managing the relation between data stored in the primary volume and differential data stored in the differential volume, and a control processor which controls read and write of data in the disk drive. The mapping information is referred to compose the data stored in the primary volume and the differential data stored in the differential volume. The composed data is sent to a backup device.

Claims

1. A backup method for use with a storage system,

the storage system comprising:

a client used by a user;

a network attached storage device which provides a file sharing service to the client;

a media server to which data recorded in the network attached storage device is backed up;

a management client which requests the network attached storage device to carry out the backup; and

a network which connects the client, the network attached storage device, the media server, and the management client to one another,

the network attached storage device comprising;

a network interface connected to the network;

a memory which stores a control program;

a disk drive having an primary volume, a differential volume, and a mapping table, the primary volume storing data sent from the client, the differential volume storing differential data of a snapshot of the primary volume, the mapping table managing the relation between data stored in the primary volume and differential data stored in the differential volume,

a disk interface connected to the disk drive to control data transfer between the client and the disk drive based on a data input/output request from the client; and

a control processor which controls read and write of data in the primary volume created from a storage area of the disk drive, which controls to write data stored in the primary volume in the past in the differential volume as differential data for the respective generations, which uses the mapping table to manage, for the respective generations, the address relation between data stored in the primary volume and differential data stored in the differential volume, and which refers to the mapping table to compose the data of the primary volume and the differential data and to create a virtual volume for the respective generations,

the backup method comprising the steps of;

controlling the management client to request to the control processor to provide a list of the generations that can be backed up;

causing the control processor to obtain a list of the generations that can be backed up by referring to the mapping table, and to send the obtained list to the management client;

controlling the management client to request to the control processor to take a backup of a generation selected from the obtained list;

controlling the control processor to search the mapping table for the designated generation and to obtain the address of data that constitutes the virtual volume;

controlling the control processor to read data stored at the obtained address; and

controlling the control processor to send the obtained data of the virtual volume to the media server.

2. A backup method for use with a storage system, the storage system comprising:

a network attached storage device which provides a file sharing service to a client used by a user;

a backup device to which data recorded in the network attached storage device is backed up;

a management client which requests the network attached storage device to take the backup; and

the network attached storage device comprising;

a memory which stores a control program;

a disk drive having an primary volume, a differential volume, and mapping information, the primary volume storing data sent from the client, the differential volume storing differential data of a snapshot of the primary volume, the mapping information managing the relation between data stored in the primary volume and differential data stored in the differential volume, and

a control processor which controls read and write of data in the disk drive,

wherein the control processor executes;

a first step of composing the data stored in the primary volume and the data stored in the differential volume by referring to the mapping information; and

a second step of sending the composed data to the backup device.

3. The backup method according to claim 2, wherein:

the mapping information manages the relation between an address of data stored in the primary volume and an address of differential data, which is associated with the primary volume, stored in the differential volume; and

the first step comprises the steps of;

obtaining the address of the differential data, which is associated with the address of the data stored in the primary volume, stored in the differential volume by referring to the mapping information,

reading from the differential volume the differential data stored at the obtained differential volume address, and

composing the data stored in the primary volume and the differential data stored in the differential volume.

4. The backup method according to claim 2, wherein:

the differential volume stores differential data of a snapshot for the respective generations;

the mapping information manages, for the respective generations, the relation between the data stored in the primary volume and the differential data stored in the differential volume;

the backup method further comprises;

a third step of controlling the management client to request to the control processor to provide information of the generations that can be backed up;

a fourth step of controlling the control processor to obtain information of the generations that can be backed up by referring to the mapping information, and to send the obtained information to the management client; and

a fifth step of controlling the management client to request to the control processor to take a backup of data of a snapshot of a generation selected from the obtained information; and

the first step comprises composing the data stored in the primary volume and the differential data stored in the differential volume for the generation designated in the backup request.

5. The backup method according to claim 4, wherein:

the first step comprises composing the data stored in the primary volume and the differential data stored in the differential volume to constitute a virtual volume for the respective generations; and

the second step comprises sending data of the virtual volume for the respective generations.

6. A storage system comprising:

a network attached storage device which provides a file sharing service to a client used by a user;

a backup device to which data recorded in the network attached storage device is backed up;

a management client which requests the network attached storage device to take the backup; and

a network which connects the client, the network attached storage device, and the backup device to one another,

the network attached storage device comprising;

a memory which stores a control program;

a disk drive having an primary volume, a differential volume, and mapping information, the primary volume storing data sent from the client, the differential volume storing differential data of a snapshot of the primary volume, the mapping information managing the relation between data stored in the primary volume and differential data stored in the differential volume; and

a control processor which controls read and write of data in the disk drive,

wherein the control processor;

compose the data stored in the primary volume and the data stored in the differential volume by referring to the mapping information; and

send the composed data to the backup device.

7. The storage system according to claim 6, wherein:

the differential volume stores differential data of a snapshot for the respective generations;

the mapping information manages, for the respective generations, the relation between an address of data stored in the primary volume and an address of differential data, which is associated with the primary volume, stored in the differential volume;

a management client requests to the control processor to provide information of the generations that can be backed up;

the control processor obtains information of the generations that can be backed up by referring to the mapping information, and sends the obtained information to the management client;

the management client requests to the control processor to take a backup of data of a snapshot of a generation selected from the obtained information; and

the control processor;

obtains, for the generation designated in the backup request, the address of the differential data, which is associated with the address of the data stored in the primary volume, stored in the differential volume, by referring to the mapping information;

reads from the differential volume the data stored at the obtained differential volume address;

composes the data stored in the primary volume and the differential data stored in the differential volume to constitute a virtual volume for the respective generations; and

sends data of the virtual volume for the respective generations.

8. A storage device that is communicably connected via a network to a client used by a user, the storage device comprising:

a memory which stores a control program;

a disk drive having an primary volume, a differential volume, and mapping information, the primary volume storing data sent from the client, the differential volume storing differential data of a snapshot of the primary volume, the mapping information managing the relation between data stored in the primary volume and differential data stored in the differential volume, and

a control unit which controls read and write of data in the disk drive,

wherein the control unit comprises;

a differential snapshot management module which obtains the address of data constituting a virtual volume by referring to the mapping information, the virtual volume being created by composing data stored in the primary volume and differential data stored in the differential volume;

a file system processing module which reads the differential data stored at the obtained differential volume address; and

a backup processing unit which sends the read data of the virtual volume to the backup device.

9. The storage device according to claim 8, wherein:

the differential volume stores differential data of a snapshot for the respective generations;

the mapping information manages, for the respective generations, the relation between an address of data stored in the primary volume and an address of differential data, which is associated with the primary volume, stored in the differential volume;

the backup processing module, upon receiving a request from the management client to provide information of generations that can be backed up, obtains information of the generations that can be backed up by referring to the mapping information, and sends the obtained information to the management client;

the snapshot management module, upon receiving a request from the management client to take a backup of data of a snapshot, obtains, for a generation designated in the backup request, an address of the differential data, which is associated with the address of the data stored in the primary volume, stored in the differential volume by referring to the mapping information to;

the file system processing module reads from the differential volume the data stored at the obtained differential volume address,

composes the data stored in the primary volume and the differential data stored in the differential volume to constitute a virtual volume for the respective generations; and

the backup processing module sends data of the virtual volume for the respective generations.

10. A computer program product for use to control a storage device that is communicably connected via a network to a client used by a user, the storage device comprising:

a memory which stores a control program;

a disk drive having an primary volume, a differential volume, and mapping information, the primary volume storing data sent from the client, the differential volume storing differential data of a snapshot of the primary volume, the mapping information managing the relation between data stored in the primary volume and differential data stored in the differential volume, and

a control unit which controls read and write of data in the disk drive,

the program controlling the control processor to execute;

a first step of composing data stored in the primary volume and differential data stored in the differential volume by referring to the mapping information; and

a second step of sending the composed data to a backup device.

11. The computer program product according to claim 10, wherein:

the differential volume stores differential data of a snapshot for the respective generations;

the mapping information manages, for the respective generations, the relation between an address of data stored in the primary volume and an address of differential data, which is associated with the primary volume, stored in the differential volume;

the program further controls the control processor to execute;

a third step of requesting to the control processor to provide information of generations that can be backed up;

a fourth step of controlling the control processor to obtain information of the generations that can be backed up by referring to the mapping information, and to send the obtained information to the management client; and

a fifth step of requesting to the control processor to take a backup of data of a snapshot of a generation selected from the obtained information,

the first step comprises the steps of;

obtaining, for the generation designated in the backup request, the address of the differential data, which is associated with the address of the data stored in the primary volume, stored in the differential volume by referring to the mapping information to,

reading from the differential volume the differential data stored at the obtained differential volume address, and

composing the data stored in the primary volume and the differential data stored in the differential volume to constitute a virtual volume for the respective generations; and

the second step comprises sending data of the virtual volume for the respective generations.