Patent ID: 8312186
Filing Date: 2012-11-13
Classification: G06F

Abstract:
1. A storage subsystem connected to a host computer via a network, comprising: a first interface unit for sending and receiving information to and from the host computer via a plurality of ports, and performing data access control processing according to commands input from each of the ports; a storage device for storing data; a second interface unit connected to the storage device, and for performing data Input/Output (I/O) processing of inputting and outputting data to and from the storage device; a plurality of controllers connected to the first interface unit and the second interface unit, and for performing data I/O processing to a plurality of virtual devices to which at least a part of a storage area of the storage device is allocated; a cache memory for temporarily storing data associated with the processing of the first interface unit and the second interface unit and the plurality of controllers; and a shared memory for storing control information to be shared by the plurality of controllers, wherein each of the controllers includes a main memory for storing the control information stored in the shared memory as control information that is common to each of the controllers, and a plurality of microprocessors for performing data I/O processing to the virtual devices according to the control information stored in the main memory, wherein, when the host computer issues a data I/O request to one virtual device among the plurality of virtual devices via each of the ports, the first interface unit specifies a controller to handle the data I/O processing to the one virtual device according to the I/O request among the plurality of controllers based on the I/O request, wherein the controller that received the I/O request selects an exclusive mode where a single microprocessor among the plurality of microprocessors exclusively performs the data I/O processing to the one virtual device, if load information concerning each of the ports shows a low load condition, wherein the controller that received the I/O request selects a shared mode where two or more microprocessors share the data I/O processing to the one virtual device, if the load information concerning each of the ports shows a high load condition, and wherein the controller performs the data I/O processing according to the selected exclusive mode or shared mode.