Patent ID: 8661214

Claim:
A storage system, which includes multiple logical volumes, the storage system comprising: a data migration processing part for executing a data migration process, which transfers data of a migration-source volume selected from among the multiple logical volumes and stores this data in a migration-destination volume selected from among the multiple logical volumes; a synchronous copy processing part for executing a synchronous copy process, which notifies a higher-level apparatus that write processing is complete after write data received from the higher-level apparatus has been written to the migration-source volume and the migration-destination volume; an asynchronous copy processing part for executing an asynchronous copy process, which notifies the higher-level apparatus that write processing is complete when write data received from the higher-level apparatus has been written to the migration-source volume, and writes thereafter the write data to the migration-destination volume; and a copy processing part, which, in a case where write data targeted at the migration-source volume is received from the higher-level apparatus during the data migration process, selects and executes one of the synchronous copy process and the asynchronous copy process based on prescribed information.