A storage system comprises multiple physical storage devices, and a power supply for the multiple physical storage devices. Each physical storage device requires an input of a first voltage and an input of a second voltage that is a lower voltage than the first voltage. The power supply comprises a first power supply circuit that is made redundant and a second power supply circuit that is made redundant. Each first power supply circuit outputs a first voltage, which is input to the respective physical storage devices. Each second power supply circuit outputs a second voltage to a storage device group (two or more physical storage devices of the multiple physical storage devices) corresponding to this second power supply circuit. Each second power supply circuit is isolated from a circuit board comprising the first power supply circuit.