Patent ID: 8443237

Claim:
A storage apparatus comprising: a controller that writes data into or reads data from a storage drive in response to a data input-output request sent from an external device; and at least one expander that includes a switch circuit having at least one physical port, the controller and the storage drive being communicatively coupled to each other through the switch circuit, wherein the controller performs a loopback diagnosis on the expander, the controller performs a connection-based diagnosis on a target device by sending the target device a connection frame, the target device being a device detected as having a failure as a result of the loopback diagnosis, when a response to the connection frame includes information indicating a failure, the controller disables the physical port to which the target device is coupled, or the physical port of the switch circuit existing on a path from the controller to the target device, and when there is a wide link in the path from the controller to the target device, the controller disables paths of the wide link except for a certain path included in the wide link, and then starts the connection-based diagnosis.