Disclosed is a method A method for controlling a storage system including a host computer; a first storage controller connected communicably to the host computer, for receiving a data frame transmitted from the host computer and executing data input to and data output from a first storage device in response to a data input/output request described in the data frame; and a second storage controller connected communicably to the first storage controller, comprising relaying by the first storage controller, upon receipt of the data frame transmitted from the host computer, the data frame to the second storage controller in response to information described in the data frame.