A clustering disk subsystem comprising a switch holding a table which can modify a destination of a request from a host computer, wherein the switch transfers an access request to another channel according to a destination channel status such as heavy load or fault, and the channel which received the request processes the request by proxy for load balancing between internal disk controllers in a clustering disk subsystem. The subsystem has an effect in which load balancing or fail-over between channels or disk controllers can be performed without any special hardware or software in the host. As a result, good performance can be obtained even when access requests from the host computer are concentrated in a specific channel or disk controller.