Patent ID: 7673096

Claim:
A virtual storage control apparatus for specifying a storage block of a real disk associated with a storage block of a virtual disk designated by a host apparatus based on a correspondence between the storage block of the virtual disk and the storage block of the real disk, and for accessing the specified storage block, the virtual storage control apparatus comprising: a storage unit storing information indicating an instruction of data integrity is set for each virtual disk; a determination unit determining, when a write request is issued from the host apparatus, whether or not the instruction of data integrity is set for a virtual disk designated by the write request by referring to the information stored in the storage unit, the virtual disk corresponding to a first real disk in which data requested by the write request is written; a write unit writing, when the instruction of data integrity is set for the virtual disk designated by the write request, the data requested by the write request in an empty block of a second real disk corresponding to the virtual disk for data integrity; and a recording unit recording write volume information indicating the second real disk in which the data requested by the write request is written, write request volume information indicating the virtual disk designated by the write request, and date and time information indicating a date and time when the data requested by the write request is written in the second real disk on a rewrite information storage unit; further comprising: a first obtaining unit obtaining, when a restore request for the virtual disk is issued designating the virtual disk and the date and time information, the write request volume information of the virtual disk by referring to the rewrite information storage unit based on the designated virtual disk; a second obtaining unit obtaining, when the first obtaining unit cannot obtain the write request volume information of the volume disk, the write volume information of the second real disk in which the data requested by the write request is written by referring to the rewrite information storage unit based on the designated date and time information; and a restore unit restoring the data of the virtual disk requested by the restore request based on the write volume information obtained by the first obtaining unit and the second obtaining unit.