In a multi controller storage system, hardware and software are updated without interruption. The storage system including a node has storage control units each including a processor, a memory, and a port; and a storage drive, and the storage control units each request data access and transmit and receive data with respect to a host computer via the ports. The processors process input and output data from the host computer, the memories store the control information in order to access the data stored in the storage drive, and the storage system transmits the control information stored in the memories to another node, stores the control information in the memories of the storage control units, and sets ports of the other node in consideration of a relationship between the storage control units and the ports of the nodes, if the other node can access data relating to the control information.