Provided is a method of controlling a computer system which includes a host computer and one or more storage systems coupled to the host computer via a network, wherein the first processor executes an application job which executes data I/O in a logical storage area; the second processor executes a management job which executes the data I/O in the logical storage area; the method comprising: judging whether at lest one of resources of the computer system used for the data I/O of the application job is also used for the data I/O of the executed management job when performance of the application job drops below a predetermined threshold; and displaying information indicating the executed management job when it is judged that at least one of the resources used for the data I/O of the application job is also used for the data I/O of the executed management job.