Patent ID: 7149787

Claim:
A method for mirroring data of a first storage area, comprising: placing a second storage area in a first state, wherein the first state of the second storage area is a state in which updates to the first storage area are made to the second storage area; mirroring data from the first storage area to the second storage area while the second storage area is in the first state; changing a state of the second storage area from the first state to a second state in which updates to the first storage area are not made to the second storage area, wherein after the changing act the second storage area contains a snapshot of data of the first storage area at a given time; restoring data to the first storage area from the second storage area while maintaining the second storage area in the second state; updating, after the restoring act is complete, data within the first storage area such that the updated data within the first storage area is different from the snapshot of data; and restoring, from the second storage area, the snapshot data to replace the updated data within the first storage area.