Patent ID: 8447937

Claim:
A computer system, comprising: a storage system; a host computer that is coupled to the storage system via a network; and a storage management server that can access to the storage system and the host computer, wherein the storage system comprises a first interface that is coupled to the network, a first processor that is coupled to the first interface, a first memory that is coupled to the first processor, and a storage device that stores data that is read or written by the host computer, and provides at least one storage area of the storage device for the host computer as at least one volume, wherein the storage management server comprises a second interface that is coupled to the storage system, a second processor that is coupled to the second interface, and a second memory that is coupled to the second processor, wherein the second memory stores configuration information of the volume and configuration information of a migration group, and wherein the storage management server executes a volume migration plan for migrating data in the volume in the migration group to another volume said storage management server: calculates a required period of time for migrating the data based on a size of data to be migrated, volume configuration information of a first volume included in the migration group in which the data to be migrated is stored, and volume configuration information of a second volume to which the data is migrated, generates the volume migration plan for the migration group by determining a start time at which the data migration starts based on the calculated required period of time and an input end time, sets a priority of the volume migration plan of the migration group, and changes, in a case where a period of time during which the volume migration plan is executed and a period of time during which an existing volume migration plan is executed are overlapped with each other, based on a result of comparing a priority of the volume migration plan with a priority of the existing volume migration plan, the start time of at least one of the volume migration plan and the existing volume migration plan, in accordance with the priority of a volume migration plan which has a higher priority of the volume migration plan and the existing volume migration plan.