GSX Server lets you take a snapshot of a virtual machine at any time and revert to that snapshot at any time.

You can take a snapshot while a virtual machine is powered on, powered off or suspended. A snapshot preserves the virtual machine just as it was when you took the snapshot — the state of the data on all the virtual machine's disks and whether the virtual machine was powered on, powered off or suspended.

When you revert to a snapshot, you discard all changes made to the virtual machine since you took the snapshot.

Use the Snapshot and Revert buttons on the console toolbar to take a snapshot and revert to it later.

You can take a new snapshot at any time. When you do so, you replace the previous snapshot. You can have only one active snapshot at a time.

For more information, including examples of ways you can use the snapshot, see Taking Snapshots.