Patent ID: 7581062

Claim:
A disk storage system, comprising: a plurality of hard disk drives for storing data and being divided to include first, second, and third logical units; at least one disk control unit for controlling storage of data in said plurality of hard disk drives; a plurality of channel control units for receiving data from an external network; a connection unit being connected with said channel control units and said at least one disk control unit; a cache memory for temporarily saving data to be transferred to and from said disk control unit; and a management terminal connected to said channel control units and said at least one disk control unit, said management terminal being configured to manage storage of data in said disk storage system, wherein each of said channel control units includes an I/O processor transmitting a block access, the first logical unit stores data for the block access transmitted from the I/O processor, the second logical unit stores information of statuses of a plurality of said I/O processors which is used when a processing is succeeded between a first one and a second one of the I/O processors, each of the second and third logical units are connected with each of the first and second I/O processors to be shared thereby, the management terminal indicates to the second logical unit a definition of a path therefrom to said second logical unit and a definition of a path therefrom to said third logical unit which backs-up data stored in the second logical unit, and one of the first and second I/O processors assumes the processing of the other if a failure occurs in the other of the first and second I/O processors by using information stored in said second logical unit and the definition of the path to said second logical unit.