Data backup method in a network storage system

• US 7,039,778 B2
• Filed: 08/15/2003
• Issued: 05/02/2006
• Est. Priority Date: 05/20/2003
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamasaki, Yasuo
• Primary Examiner(s): Anderson, Matthew D.
• Assistant Examiner(s): Krofcheck, Michael
• Application Number:
  US10/641,054
• Publication Number:
  US 20040236984A1
• Time in Patent Office: 991 Days
• Field of Search: None
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 2201/855 Details of asynchronous mirroring using a journal to transfer not-yet-mirrored changes
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

In a data backup method in a network storage system in which mirroring is conducted between two disk units, the mirroring is delayed by accumulating update data in a cache for a predetermined period of time. When storing the update data in the cache, files are related to each other, and information of file open and close is also stored. The update data is reflected in the mirrored disk using the file open and close information. As a result, the contents of the mirrored disk are delayed for a predetermined period of time from those of the primary disk, and all files are in other than the open state. Within a range of the period to store data in the cache, it is possible to restore data created at a point of time preceding a desired period of time. This enables recovery if a user erases files by mistake.

Claims

1. The information processing system An information processing system, comprising:

a processor;

a first storage apparatus which can be accessed by the processor;

a second storage apparatus which can be accessed by the processor; and

a third storage apparatus, wherein

the processor includes a control unit for conducting a backup operation from the first storage apparatus to the second storage apparatus,

the third storage apparatus includes an update log of the first storage apparatus and file open and close information for the first storage apparatus, and

the control unit conducts a rewriting operation in the second storage apparatus using the update log and the file open and close information of the first storage apparatus,

wherein the control unit prevents a write operation of a file, which is not closed after the file is opened, in the second storage apparatus using the update log of the first storage apparatus and information regarding an opening and closing time of the file of the first storage apparatus.

2. The information processing system according to claim 1, wherein the update log of the first storage apparatus includes a location to store information indicating contents of update, and time of update.

3. The information processing system according to claim 1,

wherein the control unit extracts, from the update log, an update log item having an update time at least a predetermined time before and conducts the back up operation using the extracted update log items.