Provided is a method used in a computer system which includes at least one host computer, the method including managing a job to be executed by the host computer and a power supply of the host computer, the method including the procedures of: receiving the job; storing the received job; scheduling an execution plan for the stored job; determining, based on the execution plan of the job, a timing to execute power control of the host computer; determining a host computer to execute the power control when the determined timing to execute the power control is reached; controlling the power supply of the determined host computer; and executing the scheduled job.