A data-center administrator performs an initial full backup on Sunday and incremental backups Monday through Friday. To avoid re-scanning the 25 TB file share every weekend, the backup application runs a Saturday job that creates a new full backup image entirely on the backup repository by merging the last full backup with the week's incremental files; no data is read from the production server or traverses the network. Which backup method is the administrator using?
The described process synthesizes a fresh full-backup file from backup data that already exists on the target device. Because it combines the previous full (or synthetic full) with all subsequent incrementals without pulling data from the protected server, it is a synthetic full backup. An active full backup would reacquire all source data over the network, a differential backup contains only the cumulative changes since the last full, and reverse incremental updates the existing full while storing deltas for roll-backs-none of which match the scenario.