External storage and data recovery method for external storage as well as program

• US 20060242452A1
• Filed: 06/08/2006
• Published: 10/26/2006
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: Kazuhito Suishu, Keiichi Kaiya, Masanao Tsuboki
• Original Assignee: Kazuhito Suishu, Keiichi Kaiya, Masanao Tsuboki
• Inventors: Tsuboki, Masanao, Suishu, Kazuhito, Kaiya, Keiichi
• Granted Patent: US 7,243,256 B2
• Time in Patent Office: Days
• US Class Current: 714/2
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery

Abstract

The data is automatically recovered to a desired arbitrary point in an external storage without imposing a burden on the host computer. An application on a host computer instructs data recovery control processing of a disk control apparatus to set a recovery opportunity. It is possible to register arbitrary plural points as a recoverable point by setting a recovery flag included in journal data. In the case in which data is recovered due to occurrence of a failure or the like, the application requests a list showing recovery opportunities which have already been set. The application designates a point to which data is recovered on the basis of the recovery opportunity list. The disk control apparatus recovers the data to the designated point on the basis of a backup disk and a journal disk.

Claims

1. (canceled)

2. A storage system to be connected to a host computer, comprising:

a storage device which stores data to be used by the host computer; and

a controller which controls the storage device,

wherein the controller comprises;

a memory which stores a recoverable point to be set by the host computer concerning data stored in the storage device, said recoverable point corresponding to journal data which includes journal control information having information necessary for recovering data on the storage device to the recoverable point and data size information indicating a size of write data corresponding to said journal data,

wherein said controller sends information for selection related to the journal data at the recoverable point to the host computer in response to a request from the host computer, and recovers data designated by the host computer to a designated recoverable point based on the information for selection related to the journal data at the recoverable point,

wherein the storage device includes a journal data area for storing journal data, and a backup data area for storing backup data,

wherein, if a free space of the journal data area becomes insufficient, said controller transfers oldest journal data from the journal data area to the backup data area by an amount necessary to accommodate a size of the oldest journal data based on said data size information.

3. A storage system according to claim 2, wherein the memory is capable of storing arbitrary plural points, which are set by the host computer, as the recoverable point.

4. A storage system according to claim 2, wherein the journal data area stores write data from the host computer as the journal data, and

wherein the memory stores the journal control information at a predetermined position of the journal data based on an instruction from the host computer to thereby store the recoverable point.

5. A storage system according to claim 4, wherein the journal data includes at least write data, a write position, and a recovery flag serving as the journal control information, said recovery flag being settable by the host computer to indicate that the journal data is a recoverable point.

6. An external storage according to claim 2, wherein, if the oldest journal data stored in the journal data area is transferred to the backup data area to increase the free space of the journal data area, said controller notifies the host computer that an oldest recoverable point among registered recoverable points has been changed.

7. An external storage according to claim 3, wherein if a free space of the journal data area becomes insufficient, the controller uses an unused storage area in the storage device to automatically extend a logical size of the journal data area.

8. A storage system according to claim 2, wherein the amount of the oldest journal data to be transferred by the controller is one of a predetermined amount, an amount corresponding to a speed of storing journal data and an amount corresponding to a capacity of the backup data area.

10. A storage system according to claim 2, wherein the journal control information is writing control information that includes at least information regarding a data write position and data size of write data corresponding to the journal data.

9. A storage system to be connected to a host computer, comprising:

a storage device which stores data to be used by the host computer; and

a controller which controls the storage device,

wherein the controller comprises;

a memory which stores a recoverable point to be sent by the host computer concerning data stored in the storage device, said recoverable point corresponding to journal data which includes journal control information having information necessary for recovering data on the storage device to the recoverable point and data size information indicating a size of a write data corresponding to the journal data,

wherein said controller sends information for selection related to the journal data at the recoverable point to the host computer in response to a request from the host computer and recovers data designated by the host computer to a designated recoverable point based on the information for selection related to the journal data of the recoverable point,

wherein the storage device includes a journal data area for storing journal data and a backup data area for storing backup data, and

wherein, if a free space of the journal data area becomes insufficient, said controller searches for an unused area capable of storing the oldest journal data, extends a logical size of the journal data area to a capacity of the unused storage area and updates the journal control information based on the extended logical size of the journal data area.

11. A storage system according to claim 9, wherein the memory is capable of storing arbitrary plural points, which are set by the host computer, as the recoverable point.

12. A storage system according to claim 9, wherein the journal data area stores write data from the host computer as the journal data, and

wherein the memory stores the journal control information at a predetermined position of the journal data based on an instruction from the host computer to thereby store the recoverable point.

13. A storage system according to claim 12, wherein the journal data includes at least write data, a write position, and a recovery flag serving as the journal control information, said recovery flag being settable by the host computer to indicate that the journal data is a recoverable point.

14. An external storage according to claim 9, wherein, if the oldest journal data stored in the journal data area is transferred to the backup data area to increase the free space of the journal data area, said controller notifies the host computer that an oldest recoverable point among registered recoverable points has been changed.

15. An external storage according to claim 11, wherein if a free space of the journal data area becomes insufficient, the controller uses an unused storage area in the storage device to automatically extend a logical size of the journal data area.

16. A storage system according to claim 9, wherein the amount of the oldest journal data to be transferred by the controller is one of a predetermined amount, an amount corresponding to a speed of storing journal data and an amount corresponding to a capacity of the backup data area.