Abstract: Availability of a cluster storage system to data I/O from a client apparatus is improved. In a cluster storage system including a plurality of nodes and a cluster network, each of the nodes can store data in units of volumes, the cluster storage system includes a plurality of volume groups made up of a plurality of volumes stored in the plurality of nodes, and the nodes synchronize the volumes of the same volume group via a cluster network. When communication in the cluster network is split, the node enables to access at least one volume belonging to a split volume group in which synchronization of volumes is enabled from the client apparatus.

Abstract: A computer system comprises a first computer having a first processing performed processing by using a storage region; a second computer having a second processing unit provided the storage region, manage a first port for communication with the first processing unit, and execute a processing request to the storage region; and a third computer having a third processing unit manage a second port for communication with the first processing unit. The third processing unit holds port management information for managing a correspondence relationship of the first port and the second port, selects the first port for redirecting on the basis of the port management information in a case of receiving a connection request; and transmits a response notifying the first port for redirecting to the first processing unit.