Patent ID: 7702852
Filing Date: 2010-04-20
Classification: G06F

Abstract:
1. The storage system, comprising: a control section for processing a read/write request from an external device outside the storage system; a plurality of storage media for storing data to be used by said external device; group management information that indicates the correspondence between each of said plurality of storage media and each of a plurality of storage media groups formed of a plurality of storage media; storage media management information for managing a consumption value related to writing for each of said plurality of storage media; and upper limit write management information for managing information that indicates an upper limit related to writing of each of said plurality of storage media, wherein said control section updates a consumption value in said storage media management information corresponding to a storage medium of a write destination according to writing to a storage medium, selects a storage media group out of said plurality of storage media groups, specifies a plurality of storage media constituting said selected storage media group out of said group management information, acquires a consumption value from said storage media management information for each of said specified plurality of storage media, acquires an upper limit related to writing from said storage media management information for each of said specified plurality of storage media, and computes a remaining use period value, which indicates how much longer the storage medium can be used, using said acquired consumption value and said acquired upper limit for each of said specified plurality of storage media, and shifts data in at least one storage medium out of the plurality of storage media belonging to said selected storage area group to a storage medium which is different from said storage area group, based on each of said computed remaining use period values, wherein said storage system further comprises one or more reserved storage media which do not belong to any of said plurality of storage media groups, and said control section computes a difference of the remaining use period values of two storage media out of said specified plurality of storage media, compares said difference with a first threshold value, and shifts data in a first storage medium out of the first and second storage media corresponding to said two storage media respectively to one reserved storage medium out of said one or more reserved storage media if said difference is less than said first threshold value, wherein said control section changes said first threshold value according to the write frequency to the storage media group and/or each storage medium.