Provided is a computer system which is capable of backup operation with a minimum count of volumes in a remote copy environment when a disaster or the like causes a storage system to stop working normally. The computer system has a host computer, a first storage system, a second storage system, and a management computer. The first storage system contains a data volume which stores data requested by an application to be written. The second storage system contains a mirrored volume to which data stored in the data volume is copied. The computer system is characterized by being configured to receive an input of a policy about backup processing executed in backup volumes and set a configuration of the first storage system and a configuration of the second storage system under the received policy.