An information processing system comprising an information processing device and a plurality of storage devices, the information processing device including: a storage; a communication unit configured to be able to communicate with a plurality of storage devices via a network; and a control unit including a processor and functioning, when the processor executes a control program, as: a receiving unit configured to receive an instruction from a user; a processing unit configured to generate or process data in response to the instruction received by the receiving unit; and a storage controller configured to perform storage control on the data generated or processed by the processing unit, wherein, the storage controller is configured to generate information indicating a predetermined storage device of a plurality of storage devices on a basis of an instruction received by the receiving unit and store the generated information in the storage, and the storage has a plurality of storage areas, wherein when the receiving unit receives a predetermined storage instruction, the storage controller is configured to: (i) store the generated or processed data in a storage area designate through the storage instruction among the plurality of storage areas of the storage; and (ii) when the storage area designated through the storage instruction is a predetermined storage area, control the communication unit to acquire information indicating an available capacity of the predetermined storage device from the predetermined storage device, and if it is determined that the available capacity of the predetermined storage device is equal to or lower than a predetermined threshold value, or that the storage capacity of the predetermined storage device is equal to or lower than a predetermined threshold value, generate data obtained by reducing a capacity of the generated or processed data by reducing an amount of data of said generated or processed data by an amount of reduction L, the amount of reduction L being calculated, when a constant of proportionality, a threshold value of a storage capacity, a storage capacity of the predetermined storage device, a threshold value of an available capacity of the predetermined storage device, and an available capacity of the predetermined storage device are set to A, B, C, D, and E, respectively, by a calculation expression of L = A×(B-C)×(D-E), control the communication unit to transmit the generated data to the predetermined storage device, and store the transmitted data in the predetermined storage device. a storage; a communication unit configured to be able to communicate with a plurality of storage devices via a network; and a control unit including a processor and functioning, when the processor executes a control program, as: a receiving unit configured to receive an instruction from a user; a processing unit configured to generate or process data in response to the instruction received by the receiving unit; and a storage controller configured to perform storage control on the data generated or processed by the processing unit, a receiving unit configured to receive an instruction from a user; a processing unit configured to generate or process data in response to the instruction received by the receiving unit; and a storage controller configured to perform storage control on the data generated or processed by the processing unit, wherein, the storage controller is configured to generate information indicating a predetermined storage device of a plurality of storage devices on a basis of an instruction received by the receiving unit and store the generated information in the storage, and the storage has a plurality of storage areas, wherein when the receiving unit receives a predetermined storage instruction, the storage controller is configured to: (i) store the generated or processed data in a storage area designate through the storage instruction among the plurality of storage areas of the storage; and (ii) when the storage area designated through the storage instruction is a predetermined storage area, control the communication unit to acquire information indicating an available capacity of the predetermined storage device from the predetermined storage device, and if it is determined that the available capacity of the predetermined storage device is equal to or lower than a predetermined threshold value, or that the storage capacity of the predetermined storage device is equal to or lower than a predetermined threshold value, generate data obtained by reducing a capacity of the generated or processed data by reducing an amount of data of said generated or processed data by an amount of reduction L, the amount of reduction L being calculated, when a constant of proportionality, a threshold value of a storage capacity, a storage capacity of the predetermined storage device, a threshold value of an available capacity of the predetermined storage device, and an available capacity of the predetermined storage device are set to A, B, C, D, and E, respectively, by a calculation expression of L = A×(B-C)×(D-E), control the communication unit to transmit the generated data to the predetermined storage device, and store the transmitted data in the predetermined storage device.