Patent ID: 7660957

Claim:
A system comprising: a plurality of storage systems each including a control section and storage devices whereby to have the functionality of storing data into storage areas, wherein a first storage system retains first data as replication target data, a second storage system retains second data as replication data of the first data, and a third storage system retains third data as replication data of the first data, wherein in accordance with a first instruction received from a host computer, the first storage system performs data updating of the first data, creates first information regarding the data updating, stores the first information into a storage area in the first storage system, and transfers a second instruction for data updating of the second data to the second storage system in synchronization with the data updating of the first data via a communication line between the first and second storage systems, wherein in accordance with the second instruction for the data updating, the second storage system performs the data updating of the second data, creates second information regarding the data updating, and stores the second information into a storage area in the second storage system, wherein in asynchronization with the data updating of the first and second data, the third storage system receives a third instruction from the second storage system via a communication line between the second and third storage systems, stores the second information of the third data, and performs data updating of the third data based on the third instruction, and wherein, in the event of failure occurrence, transfer of each individual information is performed between at least two of the storage systems and data updating is performed by using the transferred information.