Storage system

• US 20070179994A1
• Filed: 03/22/2006
• Published: 08/02/2007
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ninose, Kenta, Deguchi, Akira, Eguchi, Yoshiaki
• Granted Patent: US 7,571,348 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

When an event occurs in a storage system that is not recognized by a host, it is not possible to recover data at the point before and after this event. Provided is a storage system including a first storage area storing data to be used by a computer, and a second storage area for storing updated data and its update log information when there is an update request from the computer to the first storage area. This storage system monitors its own storage system and detects an event, and creates a recovery point and its update log information based on the event. When the storage system receives a recovery command at a certain recovery point, it recovers data of the first storage area at the time of recovery point by writing, in a replication storage area at a certain point of the first storage area, update data up to the recovery point among the update data stored in the second storage area.

Claims

1. A storage system connected to a computer, comprising:

a first storage area for storing data to be used by said computer;

a second storage area for storing write data and first update log information corresponding to said write data when there is a write request from said computer for writing data in said first storage area;

update data reception means for receiving said write data from said computer and writing this in said first storage area; and

update log creation means for creating said first update log information;

wherein said update data reception means detects the situation of not being able to write said write data received from said computer in said first storage area as a status change in said first storage area; and

wherein said update log creation means defines a point on and after the point in time when said update data reception means detected said status change as a recovery request point, and creates second update log information corresponding to said recovery request point.

2. The storage system according to claim 1,

wherein said update data reception means detects said status change upon receiving a certain control request from said computer;

and

wherein said update log creation means defines a point after said update data reception means receives said certain control request and before executing said certain control request as said recovery request point.

3. The storage system according to claim 2,

wherein said update data reception means detects said status change upon receiving a control request from said computer for deleting a certain data in said first storage area.

4. The storage system according to claim 1,

wherein, when said update log creation means is to define a plurality of said recovery request points, said plurality of said recovery request points is managed with a first table given a recovery request identifier for identifying said second update log information.

5. The storage system according to claim 4, further comprising recovery request point provision means,

wherein, when said recovery request point provision means receives a transmission request of information of said recovery request point from said computer, said recovery request point provision means refers to said first table and transmits said second update log information given said recovery request identifier corresponding to said recovery request point.

6. The storage system according to claim 5, further comprising recovery means,

wherein, when said computer transmits a recovery request of said first storage area in said recovery request point based on said recovery request identifier received from said recovery request point provision means, said recovery means recovers said first storage area in said recovery request point.

7. A storage system connected to a computer, comprising:

a first storage area for storing data to be used by said computer;

a second storage area for storing write data and first update log information corresponding to said write data when there is a write request from said computer for writing data in said first storage area;

storage area management means for managing the usage status of said first storage area; and

update log creation means for creating said first update log information;

wherein said storage area management means detects a status change in said first storage area when an access request from said computer to said first storage area is suspended; and

wherein said update log creation means defines a point on and after the point in time when said storage area management means detected said status change as a recovery request point, and creates second update log information corresponding to said recovery request point.

8. The storage system according to claim 7,

wherein, when said update log creation means is to define a plurality of said recovery request points, said plurality of said recovery request points is managed with a first table given a recovery request identifier for identifying said second update log information.

9. The storage system according to claim 8, further comprising recovery request point provision means,

wherein, when said recovery request point provision means receives a transmission request of information of said recovery request point from said computer, said recovery request point provision means refers to said first table and transmits said second update log information given said recovery request identifier corresponding to said recovery request point.

10. The storage system according to claim 9, further comprising recovery means,

wherein, when said computer transmits a recovery request of said first storage area in said recovery request point based on said recovery request identifier received from said recovery request point provision means, said recovery means recovers said first storage area in said recovery request point.

11. A storage system connected to a computer, comprising:

a first storage area for storing data to be used by said computer;

a second storage area for storing write data and first update log information corresponding to said write data when there is a write request from said computer for writing data in said first storage area;

monitoring means for detecting a status change in said storage system; and

update log creation means for creating said first update log information;

wherein, said update log creation means defines a point on and after the point in time when said monitoring means detected said status change as a recovery request point, and creates second update log information corresponding to said recovery request point.

12. The storage system according to claim 11, further comprising communication means for transmitting and receiving control information to and from said computer,

wherein said monitoring means detects said status change upon receiving control information showing a failure from said communication means as a result of performing polling to said communication means.

13. The storage system according to claim 11,

wherein, when said update log creation means is to define a plurality of said recovery request points, said plurality of said recovery request points is managed with a first table given a recovery request identifier for identifying said second update log information.

14. The storage system according to claim 13, further comprising recovery request point provision means,

wherein, when said recovery request point provision means receives a transmission request of information of said recovery request point from said computer, said recovery request point provision means refers to said first table and transmits said second update log information given said recovery request identifier corresponding to said recovery request point.

15. The storage system according to claim 14, further comprising recovery means,

wherein, when said computer transmits a recovery request of said first storage area in said recovery request point based on said recovery request identifier received from said recovery request point provision means, said recovery means recovers said first storage area in said recovery request point.

16. The storage system according to claim 11, further comprising a second table for storing identifying information showing the type of said status change with respect to each of a plurality of said status changes detected by said monitoring means,

wherein said monitoring means detects said status change upon referring to said second table and control information transmitted and received in said storage system coincides with said identifying information stored in said second table.

17. A storage system connected to a computer and another storage system, comprising:

a first storage area for storing data to be used by said computer;

a second storage area for storing write data and first update log information corresponding to said write data when there is a write request from said computer for writing data in said first storage area;

notice reception means for receiving a notice transmitted from said other storage system; and

update log creation means for creating said first update log information;

wherein, when said storage system transfers data contained in said first storage area to said other storage system and said other storage system detects a status change, said notice reception means receives a notice of said status change from said other storage system; and

wherein said update log creation means defines a point on and after the point in time when said notice reception means received the notice of said status change as a recovery request point, and creates second update log information corresponding to said recovery request point.

18. The storage system according to claim 17,

wherein said other storage system has a third storage area for storing data in said first storage area transferred from said storage system;

wherein said other storage system detects the suspension in the storage of data in said third storage area as said status change and notifies this to said notice reception means;

wherein said notice reception means detects a status change in said first storage area when the notice of said status is received from said other storage system; and

wherein said update log creation means defines a point on and after the point in time when said notice reception means detected said status change as a recovery request point.

19. The storage system according to claim 17,

wherein, when said update log creation means is to define a plurality of said recovery request points, said plurality of said recovery request points is managed with a first table given a recovery request identifier for identifying said second update log information.

20. The storage system according to claim 19, further comprising recovery request point provision means,

wherein, when said recovery request point provision means receives a transmission request of information of said recovery request point from said computer, said recovery request point provision means refers to said first table and transmits said second update log information given said recovery request identifier corresponding to said recovery request point.

21. The storage system according to claim 20, further comprising recovery means,

wherein, when said computer transmits a recovery request of said first storage area in said recovery request point based on said recovery request identifier received from said recovery request point provision means, said recovery means recovers said first storage area in said recovery request point.

22. A data control method in a storage system connected to a computer and having a first storage area and a second storage area, comprising the steps of:

storing data to be used by said computer in said first storage area;

storing write data and first update log information corresponding to said write data in second storage area when there is a write request from said computer for writing data in said first storage area;

detecting a status change in said first storage area when it is not possible to write said write data received from said computer in said first storage area; and

defining a point on and after the point in time when said status change was detected as a recovery request point, and creating second update log information corresponding to said recovery request point.