Patent ID: 8095760

Claim:
A storage system for storing data, the storage system comprising: a plurality of storage devices for storing the data that is compliant with a communication protocol for peer to peer communication between daisy chain connected devices; a controller device that, compliant with the communication protocol, controls the plurality of storage devices; a plurality of expanders, on data transfer pathways between the controller device and plurality of storage devices, that connect the controller device and the plurality of storage devices by daisy chain connection compliant with the communication protocol; and a path adjusting unit that adjusts the number of expanders on one of said data transfer pathways between the controller device and one of said storage devices; wherein the path adjusting unit includes: a target specifying unit that specifies target data to be targeted for adjustment from among data stored in the plurality of storage devices; a destination selecting unit that selects, from among the plurality of storage devices, a storage device in which to store the specified target data to reduce the number of expanders on a data transfer pathway for the specified target data; and a data migrating unit that migrates the specified target data to the selected storage device; and wherein the target specifying unit includes a third specifying unit that, when the amount of data stored in the storage system exceeds a prescribed value, specifies, as the target data to be targeted for adjustment, data stored in a storage device for which a number of expanders on a data transfer pathway to the controller device exceeds a prescribed number.