EXTERNAL STORAGE AND DATA RECOVERY METHOD FOR EXTERNAL STORAGE AS WELL AS PROGRAM

• US 20090049262A1
• Filed: 10/20/2008
• Published: 02/19/2009
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tsuboki, Masanao, Suishu, Kazuhito, Kaiya, Keiichi
• Granted Patent: US 7,873,860 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• 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. 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.