US Patent 7415589 Data processing system with multiple storage systems

A data processing system has a plurality of storage systems. In this system, data replication is performed at high speed and efficiency while maintaining data integrity. In addition, when failure has occurred in a configuration element, the time necessary to resume the data replication is reduced. In accordance with an instruction from first host computer, updating of replication-target data and creation of a journal are performed in a storage system A; and updating of replication data and creation of a journal are performed in a storage system B. A storage system C retrieves a journal from the storage system B in asynchronization with the updating, and performs updating of replication data. When failure has occurred in the storage system B, a journal-retrieving end is altered to the storage system, and the replication data is updated in accordance with the retrieved journal.