Patent ID: 7865676

Claim:
A storage controller for creating, in a storage area provided by a storage device, plural logical volumes that are logical areas data is input/output to/from, providing the logical volumes to a host computer, and controlling data I/O to/from the logical volumes according to a request from the host computer, wherein the storage controller comprising: plural control units each controlling data I/O to/from the logical volume allocated to that control unit; a load monitor unit for monitoring the state of a load on each control unit; and a changer unit for changing the control unit allocated to the logical volumes to another control unit so that loads on the control units are equalized, wherein if another logical volume has a content-related connection with an allocation change candidate logical volume, the changer unit makes the control unit allocated to the allocation change candidate logical volume and the control unit allocated to another logical volume that has a content-related connection with the allocation change candidate logical volume to be the same control unit.