Patent ID: 8291189
Filing Date: 2012-10-16
Classification: G06F

Abstract:
1. A storage system, comprising: a plurality of storage devices based on a pool; and a controller; wherein said pool consists of a plurality of real pages, wherein said controller provides a virtual volume consisting of a plurality of virtual pages to a computer, wherein, in provisional real page write processing to be performed when the storage system receives a write data element which is transmitted by the computer, the controller: selects real pages among the plurality of real pages to allocate to a write destination virtual page which is a virtual page among the plurality of virtual pages, and allocates the selected real pages to the write destination virtual page, manages the write destination virtual page as though a state of the write destination virtual page is uncompressed, and stores said write data element to said allocated real pages, and wherein, in compression processing to perform asynchronously with said controller receiving said write data element, the controller: calculates whether the write destination virtual page is uncompressed, and decides with a compression virtual page for processing about the write destination virtual page, where the write destination virtual page is calculated as being uncompressed, specifies a real page which is allocated to the compression virtual page, and reads a write data element from said real page which has been specified, compresses the read write data element, selects a real page among the plurality of real pages to allocate to the compression virtual page, allocates the selected real page to the compression virtual page, and manages the compression virtual page as though a state of the compression virtual page were compressed.