In the conventional storage system, consistency is ensured only for writing from a single storage. Asynchronous remote copying and local replication are also alternately suspended in the conventional system, so that the suspension time increases and the volume in which consistency is obtained becomes old. Two local replicas are prepared, for a volume containing stored data that is transferred from the main site by asynchronous remote copying, in the storage at the sub-site. Each pair of local replicas is alternately suspended by a time-specific suspension command according to the time of the timestamp attached to the write data, and replica data in which the time sequence is secured is continually prepared. When a failure occurs at the main site, the data is recovered using the replica data.