The disclosed method includes obtaining a result concerning a busy rate and the number of accesses per unit time for a storage device including first and second storage areas; determining, from the result, whether an event that a first indicator value for the busy rate is reset occurs; when the event occurred, notifying a controller that makes the number of accesses for the second storage area not greater than the notified number of accesses of the first number of accesses less than the second number of accesses, which was notified immediately before; obtaining another result; updating the first indicator value based on another result; calculating the third number of accesses so that a sum of busy rates corresponding to the third number of accesses and corresponding to the designated number of accesses becomes equal to the updated first indicator value; and notifying the controller of the third number of accesses.