Patent ID: 8001344

Claim:
A storage control apparatus that creates a generation backup of a predetermined storage, comprising: a first copy section that creates a snapshot of all data stored in the predetermined storage at a start time of a snapshot session in a first storage; a second copy section that creates a mirror of difference data stored in the predetermined storage in a second storage, the difference data being updated by an update during a difference mirror session; a controller that, upon receiving an instruction for starting of the generation backup, starts the snapshot session and the difference mirror session, and upon receiving an instruction for overwriting first data stored in the predetermined storage with second data during the difference mirror session, causes the first copy section to copy the first data stored in the predetermined storage into the snapshot, executes the overwriting after the copying of the first data, and causes the second copy section to copy the second data stored in the predetermined storage into the mirror of the difference data after the overwriting; a third copy section that creates a mirror of latest data of all data stored in the predetermined storage during a mirror session in a third storage; and a fourth copy section that creates a snapshot of second difference data stored in the predetermined storage at a start time of a difference snapshot session in a fourth storage, the second difference data being updated during the difference snapshot session, wherein when receiving the instruction for the starting of the generation backup, the controller starts the mirror session and the difference snapshot session, and when receiving the instruction for the overwriting during the difference snapshot session, the controller causes the fourth copy section to copy the first data stored in the predetermined storage into the snapshot of the second difference data before the overwriting and causes the third copy section to copy the second data stored in the predetermined storage into the mirror of the latest data after the overwriting.