US Patent 7606971 Storage control apparatus and external storage apparatus

A storage control apparatus includes a plurality of temporary storage units that are managed in a redundant manner by data mirroring, and temporarily store data input from an outside source; a temporary-storage control unit that controls input and output of the data to the temporary storage units; and a mirroring control unit that controls the data mirroring between the temporary storage units, checks, when performing the data mirroring, validity of the data stored in a temporary storage unit of a mirroring source, and executes, when the validity of the data has been confirmed, the data mirroring.