Storage sub-system, host computer, storage system, load balancing method and load balancing program

To provide a storage system capable of performing load balancing processing in which a host computer and a storage sub-system cooperate with each other. A controller of the storage sub-system includes functions of generating and updating periodically a load balancing request table, and sending the load balancing request table to the host computer upon request of the host computer. The host computer includes a load balancing performing unit for requesting the storage sub-system to send the load balancing request table, and performing load balancing in accordance with information included in the load balancing request table when a host bus adapter identifying information in the load balancing request table sent by the storage sub-system in response to the request includes information corresponding to a host bus adapter thereof.