1. A method for controlling an information processing system, the information processing system including a first storage apparatus and a first information processing apparatus that accesses the first storage apparatus installed on a first site, a second storage apparatus and a second information processing apparatus that accesses the second storage apparatus installed on a second site, and a third storage apparatus and a third information processing apparatus that accesses the third storage apparatus installed on a third site, the method comprising the steps of: communicatively connecting the first, second and third information processing apparatuses; communicatively connecting at least two pairs of ones of the first, second and third storage apparatuses; configuring the first, second and third information processing apparatuses in a cluster for control; and setting one of the first, second and third storage apparatuses as a replication source storage apparatus, and other two of the storage apparatuses as replication destination storage apparatuses, wherein, upon receiving a data write request from one of the information processing apparatuses, the replication source storage apparatus stores data, the replication source storage apparatus sends the data to the two replication destination storage apparatuses, and upon receiving the data from the replication source storage apparatus, the two replication destination storage apparatuses store the data, such that a copy of the data stored in the replication source storage apparatus is stored in the two replication destination storage apparatuses, and when a failover is executed from one of the first, second and third information processing apparatuses to another of the first, second and third information processing apparatuses, settings of the first, second and third storage apparatuses as the replication source storage apparatus and replication destination storage apparatuses are automatically changed such that the replication source storage apparatus is switched to serve as a replication destination storage apparatus and one of the two replication destination storage apparatuses is switched to serve as a replication source storage apparatus.