A computer
system includes a primary site having a primary volume, and having an instance that performs
data processing related to input / output data, and a
secondary site having a secondary volume, and having an instance. Remote copy is set up between the primary and secondary volumes, and the instance of the primary site transfers
data input to or outputted from the primary volume to the
secondary site, while the instance of the
secondary site stores the transferred data in the secondary volume. The computer
system further includes a specifications changing section that changes specifications of the instance of the secondary site when a
failover switching process of switching a performer of the
data processing from the primary to secondary site is performed, or when a failback switching process of switching the performer of the
data processing from the secondary to primary site after the
failover switching process is performed.