Multiple storage apparatuses each provide a virtual logical volume composed of multiple logical pages to a host computer. A management computer determines a target logical page to which data are migrated to achieve a volume goal performance on the basis of access path information that can identify a storage apparatus that receives an I/O request in which the virtual logical volume is specified, an actual volume response performance, the volume goal performance to be attained, a page response performance of the logical page, and storage destination information that can identify a storage apparatus in which a storage area allocated to the logical page is present, and migrates data of the logical page between storage apparatuses.
