Patent ID: 7007147

Claim:
A data relocation method in a system, wherein the system comprises a plurality of storage systems each comprising a storage controller and at least one disk, and a manager coupled to the plurality of storage systems, the data relocation method comprising the steps of: at one source storage system of the plurality of storage systems, determining whether or not data relocation from a source storage area in the source storage system to another storage area in another one of the plurality of storage systems is necessary; when the data relocation is determined to be necessary, reporting the determined necessity from the source storage system to the manager; at the manager, selecting a target storage area, to which data stored in the source storage area is migrated, among storage areas in other storage systems; migrating data stored in the source storage area to the selected target storage area, wherein the manager has volume information associated with each of volumes in the plurality of storage systems, and in the selecting step, the manager selects the target storage area based on the volume information.