Patent ID: 8601224

Claim:
A control unit for a storage apparatus, the storage apparatus including a plurality of control units, the control unit comprising: a storage unit to store a management table to register entry information having information indicating a function of a command being executed by one of the control units in the storage apparatus related with identification information of the one of the control units that is executing the command; an accepting unit to accept a command from a control terminal; a receiving unit to receive from another control unit a request to add entry information having information indicating a function of a command being executed by the other control unit in the storage apparatus to the management table; an operating unit to register entry information corresponding to the accepted command on the management table when information indicating a function of the accepted command is not registered on the management table, and to register the received entry information on the management table when the request to add the entry information to the management table is received from the other control unit; a processor to return to the control terminal a response indicating that the accepted command is not executed when information indicating the function of the accepted command is registered on the management table, and to execute the accepted command when the function of the accepted command is not registered on the management table; and a notification unit to notify the other control unit in the storage apparatus of the entry information corresponding to the accepted command registered on the management table, and wherein when a failure of processing of the accepted command occurs in the control unit, the processing is executed by the other control unit and the control unit is notified of execution of the processing by the other control unit through entry information synchronized between the control units, and wherein the entry information is updated after completion of the processing and shared between the control units.