| 摘要 |
PROBLEM TO BE SOLVED: To provide a virtual storage device which uses a storage region efficiently.SOLUTION: The virtual storage device comprises: a releasable region deciding section 11 to which a physical region is allocated by referring to management information 171 that correlates allocation information representing a state of allocating the physical region to a management unit region with release candidate region information representing whether the management unit region is a release candidate region, to each of the management unit regions consisting a virtual logic volume, and that decides whether the management unit region being the release candidate region is a releasable region; a determining section 12 that determines whether the management unit region decided to be the releasable region is an all-zero region in which all data are zero in a management object region; and a releasing section 13 that releases allocation of the physical region allocated to the management unit region determined to be the all-zero region. |
