Patent ID: 7707456

Claim:
A storage system connected to a host computer, comprising: a plurality of first disk drives for storing data; a plurality of first controllers that receive an I/O request from said host computer and controls a plurality of first logical units configured by said plurality of first disk drives; a first memory that stores configuration information, failure information, and storage system replacement information, wherein said configuration information indicates relationships between said first logical units and said first disk drives, wherein said failure information indicates a failure status of each of said first controllers and said first disk drives, and wherein said storage system replacement information indicates a first threshold value of said failure status of said first controllers and a second threshold value of said failure status of said first disk drives for replacing said storage system with another storage system; and a connection interface unit to be connected to said another storage system, said another storage system comprising a plurality of second disk drives for storing data, a plurality of second controllers for controlling a plurality of second logical units configured by said second disk drives, and a second memory, wherein, when a failure occurs in any one of said plurality of first controllers or any one of said plurality of first disk drives, resulting in a faulty first controller or a faulty first disk drive, respectively, said failure status of said faulty first controller or said failure status of said faulty first disk drive in the failure information is updated, and wherein when said failure status of said first controllers in said undated failure information exceeds said first threshold value or said failure status of said first disk drives in said updated failure information exceeds said second threshold value, said configuration information stored in said first memory is sent to said another storage system through said connection interface unit so that said configuration information is stored in said second memory, and then data stored in said first disk drives which configure said first logical units is sent to said another storage system so that said data is stored in said second disk drives through said connection interface unit, and consequently, said another storage system processes said I/O request from said host computer instead of said storage system.