Patent ID: 9268498
Filing Date: 2016-02-23
CPC Classification: G06F

Claim Text:
1. A storage controller comprising: a processor, wherein the processor: performs a copy process in which a copy destination virtual volume is created by copying a virtual volume to which a storage area of a storage device is variably allocated in accordance with a volume use status in accordance with a copy instruction; performs a release process in which allocation of a copy destination storage area to a corresponding area of the copy destination virtual volume that corresponds to an unallocated area to which a copy source storage area is not allocated, among areas of a copy source virtual volume at a time point when the copy instruction is received is released, in the copy process; manages information that represents one or more update areas of the copy destination virtual volume updated before the copy process and the release process are performed and after the copy instruction; specifies an unallocated area for which a corresponding area includes the one or more update areas among one or more unallocated areas of the copy source virtual volume; and suppresses the release of the allocation of the copy destination storage area to the corresponding area corresponding to the specified unallocated area in the release process.