Patent ID: 8122288

Claim:
A redundant system comprising: a first apparatus arranged in a redundant configuration with a second apparatus; and a control unit that controls a power supply unit that supplies power to the first apparatus, wherein the control unit is not redundant with the first apparatus or the second apparatus, wherein: the first apparatus includes a state management unit that manages operational state information indicating an operational state of the first apparatus, and a response unit that returns the operational state information managed by the state management unit to the control unit in response to a request of the operational state information by the control unit, and the control unit includes a first requesting unit that requests the first apparatus that operates as an operation system for the operational state information, a first determination unit that determines whether the response by the response unit to the request by the first requesting unit is returned within a predetermined time, a second determination unit that determines whether the operational state indicated by the operational state information as the response to the request by the first requesting unit is normal if the first determination unit determines that the response to the request by the first requesting unit is returned within the predetermined time, and a shutdown unit that shuts down the power supply to the first apparatus, to which the first requesting unit has requested for the operational state information, if the second determination unit determines that the operational state indicated by the operational state information as the response to the request by the first requesting unit is not normal.