Patent ID: 7069383

Claim:
A storage system comprising: plural physical disk devices to which plural logical disk devices are allocated; and a storage controller coupled to the plural physical disk devices and including a memory, wherein each of the plural logical disk devices is a target device of an access from a data processing unit coupled to the storage system, and wherein the storage controller is configured to determine a need for reallocation of logical disk devices between a first logical disk device and a second logical disk device based on access information about access activity to said logical disk devices in said physical disk devices, a first access activity of said first logical disk device being different from a second access activity of said second logical disk device, transfer data of the first logical disk device to physical disk devices to which the second logical disk device is allocated, through the memory of the storage controller, and transfer data of the second logical disk device to physical disk devices to which the first logical disk device is allocated, through the memory of the storage controller, so that the first logical disk device and the second logical disk device are reallocated.