Patent ID: 8225066

Claim:
A storage system being coupled communicatively to an external device and providing a storage area to be used by the external device, comprising: a plurality of storage apparatuses of different performance capabilities, each having a storage medium that provides the storage area; and a storage controller holding storage cost coefficients of the respective storage apparatuses, the storage cost coefficients being indices of utilization costs required in use of the respective storage apparatuses, and being set in accordance with the performance capabilities of the respective storage apparatuses, user cost allocation information for each user using the storage system from the external device, the user cost allocation information being an index of an available space amount for the user from all of the storage apparatuses, and user cost distribution information that defines, for each user, proportions of the available space amount distributed to the storage apparatuses, the storage controller calculating an ideal utilization for each user, from the storage cost coefficients and the user cost distribution information, the ideal utilization being information indicating ideal utilization allotment of each of the storage apparatuses for the user, and the storage controller allocating, for each user, the ideal utilization to each of the storage apparatuses, in the order of the performance capabilities from highest to lowest.