Storage system for suppressing failures of storage media group

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,
• further comprising a cache memory area for temporarily storing write target data from an external device, wherein
• said control section stores a plurality of write target data which are stored in said cache memory area and which do not match data in each of said storage media into storage media in a predetermined sequence respectively,
• compares said computed remaining use period value and a second threshold value for a write destination storage medium of a certain write target data out of said plurality of write target data, and
• moves a sequence of said certain write target to be later than said sequence if said remaining use period value is less than said second threshold value.

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 consumption value is at least one of a write count, erase count and defective area size,
• said group management information includes a RAID configuration of each storage media group,
• 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
• specifies said RAID configuration of said selected storage media group from said group management information and selects said two or more storage media from said plurality of storage media constituting said storage media group based on said specified RAID configuration,
• computes a difference between two remaining use period values of the shortest remaining use period value and the second shortest remaining use period value out of two or more remaining use period values corresponding to said two or more storage media respectively,
• compares said difference and said first threshold value, and shifts data in a first storage medium out of the first and second storage media which correspond to said two remaining use period values 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, and
• said first threshold value is a value which makes a second time length from failure of the storage medium of which remaining use period value is shorter out of said two storage media up to the completion of data shift to said reserved storage medium to be shorter than a first time length up to failure of the storage medium of which remaining use period value is longer.