Patent ID: 8595431
Filing Date: 2013-11-26
Classification: G06F

Abstract:
1. A storage system comprising: a plurality of storage devices; and a controller that provides a virtual logical unit including a plurality of virtual storage areas to a host computer, and manages one or more logical devices configured on a physical storage area provided by said storage devices, and a storage pool including said logical devices; wherein in response to receiving a write command which requests to write data to said virtual logical unit, said controller allocates a logical storage area in said storage pool to a virtual storage area of said virtual logical unit on an allocation size basis, and writes data to said allocated logical storage area, wherein said controller releases said allocated logical storage area from said virtual storage area of said virtual logical unit on said allocation size basis, if data stored in said allocated logical storage area is a specific data pattern, and wherein after said allocated logical storage area is released from said virtual storage area, in response to receiving a first read command which requests to read data from said virtual storage area, said controller returns said specific data pattern to said host computer.