The computer system includes a node including a processor and a memory, and the processor and the memory serve as arithmetic operation resources. The computer system has an application program that operates using the arithmetic operation resources, and a storage controlling program that operates using the arithmetic operation resources for processing data to be inputted to and outputted from a storage device by the application program. The computer system has use resource amount information that associates operation states of the application program and the arithmetic operation resources that are to be used by the application program and the storage controlling program. The computer system changes allocation of the arithmetic operation resources to the application program and the storage controlling program used by the application program on the basis of an operation state of the application program and the use resource amount information.