Patent ID: 7945748

Claim:
A data processing system comprising: a storage system providing a virtual logical volume; a host computer arranged to input data to the virtual logical volume; and a management server coupled to the host computer, configured to manage the virtual logical volume, wherein the storage system comprises: a first pool configured from a plurality of physical disks and comprising a plurality of segments, each respective segment with a respective capacity; and a second pool configured from a plurality of physical disks and comprising a plurality of segments, each respective segment with a respective capacity, wherein the virtual logical volume is assigned as a current capacity one or more of the segments of a storage region in the first pool, in response to a request from the host computer upon inputting data, wherein the management server is configured so that it: (A) confirms a connection status of the host computer and the virtual logical volume, upon migrating data corresponding to the virtual logical volume, from the storage region in the first pool to another storage region in the second pool; and (B) transmits to the storage system, as a reservation capacity, a preset maximum capacity of the one or more segments to be assigned to the virtual logical volume requested by the host computer, when the host computer and the virtual logical volume are coupled, and transmits to the storage system, as the reservation capacity, the current capacity of assigned one or more segments in the virtual logical volume which is currently assigned to the virtual logical volume, when the host computer and the virtual logical volume are not coupled, wherein the storage system reserves a part of the another storage region, of which capacity is the reservation capacity transmitted from the management server, and wherein the storage system executes the migration of the data corresponding to the virtual logical volume from the storage region in the first pool to the part of the another storage region in the second pool, after the reservation of the part of the another storage region.