Provided is a storage system including: a first interface connected to a host computer; a second interface connected to a manager terminal; a control unit connected to the first interface and the second interface and equipping a processor and a memory; and one or more disk drives in which data that is requested to read by the host computer is stored, in which the control unit detects an access from the host computer to the first interface and an access from the manager terminal to the second interface, and generates log data of operations according to the accesses. Accordingly, log data concerning every action and every operation of the storage system is maintained and stored.