US Patent 7716183 Snapshot preserved data cloning

A method and device for cloning snapshots is provided. A new snapshot can be created by cloning an existing snapshot. The clone snapshot may use the preserved data of the existing snapshot, thereby obviating the need to copy the preserved data. Additionally, the clone snapshot may be created with a data structure for storing write data. Since the clone snapshot initially has no write data to store, the creation of the entire clone snapshot can be accomplished without copying any preserved data or write data from the existing snapshot, thereby increasing the efficiency with which a clone snapshot can be created.