Provided is a computer system in which power consumption of the system can be reduced and which can smoothly supply data for a request from a client and avoid increase in a failure rate. In the computer system, by maintaining a power activation threshold for activating a stopping server blade and load balance threshold for assigning the request to a server blade, a server blade whose power is activated but to which the request from the client is not assigned is previously arranged. Priorities of the server blades are maintained, and are periodically changed or are changed in accordance with operation information such as total operation time and the number of times of activation/stop. Further, by maintaining the power activation threshold and a power stop threshold, possibilities of the unbalance among the activated/stopped server blades and frequent control of the activation/stop only in a part of server blades are avoided.