Disks and data
Snapshot
An instant copy of the whole VPS: roll back in a minute, e.g. before an update.
A snapshot records the VPS disk state at one moment. If something breaks after a system or site update, the server can be rolled back to the snapshot in minutes.
Snapshots are usually stored next to the server and meant for quick rollbacks, not long-term storage — not a full replacement for backups.