Patent ID: 8495325

Claim:
A computer system comprising: a source storage subsystem including a plurality of source ports and a migration source logical unit configured to store data; a target storage subsystem including a plurality of target ports and a migration target logical unit configured to store the data migrated from the migration source logical unit via a data line coupling the source storage subsystem and the target storage subsystem; a host computer including a plurality of host ports, wherein a plurality of access paths for transmitting and receiving data to and from the migration source logical unit are formed via the plurality of host ports and the plurality of source ports; a management computer including a path migration control unit; and a fabric connection device including a fiber channel switch for mutually coupling the plurality of host ports of the host computer, the plurality of source ports of the source storage subsystem, and the plurality of target ports of the target storage subsystem; wherein the path migration control unit is configured to: set a status of the first one of the access paths to an unavailable state, set a first next access path, which is used instead of the first one of the access paths in an available state between the first one of the host ports and the first one of the target ports, set the first next access path to an available state; and the path migration control unit is further configured to: set a status of the second one of the access paths to an unavailable state, set a second next path, which is used instead of the second one of the access paths in an available state, between the second one of the host ports and the second one of the target ports, set the second next access path to an available state.