Patent ID: 8782361

Claim:
A management server which is mutually coupled via a network to each of a plurality of storage apparatuses, a backup server for storing data stored in the storage apparatuses to a backup device, and a plurality of host apparatuses which request data writing to the plurality of storage apparatuses, the management server comprising: a backup capacity calculation unit for calculating, on the basis of duplicate information on the data stored in the storage apparatuses, a backup capacity of the data if duplicate data is removed; a migration source data determination unit for determining, on the basis of the backup capacity of the data calculated by the backup capacity calculation unit, migration target data which is a target for migration among data stored in one of the storage apparatuses; and a migration destination storage apparatus determination unit for determining, on the basis of data duplicate information on the migration target data and data of a storage apparatus which is a migration destination for the data, a migration destination storage apparatus for the data.