A method and apparatus for performing data migration in storage systems implementing the remote copy function, and virtualizing existing storage devices in a new storage system after migrating the existing storage devices. According to the invention when a new storage system is connected to an old storage system destined for replacement, and prior to starting data migration, remote copy configuration information from the old storage system is migrated to the new storage system. This allows either the new storage system or the old storage system, depending on configuration, to maintain an operational remote copy function with a remote storage system during the data migration. Thereafter, data is migrated from the old storage system as a virtual volume to the new storage system while data is being transferred between the new storage system and the remote storage system in accordance with the remote copy configuration information.