.... The engine stores a single, full-size copy of production data on the specialized ZFS filesystem. Using the copy-on-write capabilities of ZFS, the DLE is able to generate full-size replicas of the production database in seconds. These writable "thin clones" will behave identically to production: they will have the same data and generate the same query plans. Instances of the Database Lab Engine (DLE) and all thin clones reside completely within your own infrastructure at all times.