A computer system including a first storage system connected to a first host computer, a second storage system connected to a second host computer and a third storage system connected to the first and second storage systems. The second storage system sets transfer setting before an occurrence of a failure, the transfer setting being provided with a dedicated storage area to be used for transferring data to the third storage system by asynchronous copy in response to a failure at the first host computer. Before the start of data transfer between the second storage system and third storage system to be executed after an occurrence of the failure, the second storage system checks the dedicated storage area, data transfer line and transfer setting information, and if an abnormal state is detected, this abnormal state is reported to the host computer as information attached to the transfer setting.