Computer system, and arrangement of data control method

A computer system include a service server, a storage server and a management server, wherein the service server includes a operating system, wherein the operating system includes a cache driver, wherein the storage server manages a plurality of tiered storage areas each having an access performance different from one another, wherein the management server includes an alert setting information generation part for generating alert setting information for the service servers to transmit alert information notifying a trigger to change an arrangement of data in accordance with a state of the service, and a control information generation part for generating cache control information including a first command for controlling an arrangement of cache data on a storage cache and tier control information including a second command for controlling an arrangement of the data on the plurality of tiered storage areas.