Storage controller, control method of the same, and information processing system

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EP 1 990 721 A8

(12)	CORRECTED EUROPEAN PATENT APPLICATION
	Note: Bibliography reflects the latest situation

(15)	Correction information:
	Corrected version no 1 (W1 A1)

(48)	Corrigendum issued on:
	04.03.2009 Bulletin 2009/10

(43)	Date of publication:
	12.11.2008 Bulletin 2008/46

(21)	Application number: 08250139.6

(22)	Date of filing: 11.01.2008

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International Patent Classification (IPC):

G06F 11/14^(2006.01)

G06F 3/06^(2006.01)

(84)	Designated Contracting States:
	AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR
	Designated Extension States:
	AL BA MK RS

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Priority:

11.05.2007 JP 2007126347

(71)	Applicant: Hitachi, Ltd.
	Tokyo 100-8280 (JP)

(72)	Inventors:
	Kawamura, Shunji Tokyo 100-8220 (JP) Homma, Hisao Tokyo 100-8220 (JP)

(74)	Representative: Hodsdon, Stephen James et al
	Mewburn Ellis LLP York House 23 Kingsway London WC2B 6HP London WC2B 6HP (GB)

(54)	Storage controller, control method of the same, and information processing system

(57) In the storage controller (1) of the present invention, different difference bitmaps (6A) are used for predetermined sections respectively, whereby the difference between the primary volume (3) and the base volume (4) is managed for each section, and the data are protected efficiently. The difference between the primary volume and the base volume is managed by using the difference bitmaps that are different for the respective sections. The journal data after a lapse of the targeted protection period are written to the base volume and then discarded. At the time of recovery, the difference bitmaps (6B) are merged to create a new difference bitmap, and the difference is copied from the base volume to the primary volume. Thereafter, the journal data up to the designated restoration point are written to the primary volume.