Backups you can actually restore

A backup that has never been restored is a hope, not a backup.

What to copy

On a small server the list is short: the configuration you wrote by hand, the data the service created and the script that installs everything else. Packages and binaries can be downloaded again, so they do not belong in the archive.

Where to keep it

A copy that lives on the same machine protects against a typo and nothing else. Keep at least one copy somewhere the server cannot delete: another provider, or a computer at home that pulls the archive on a schedule.

How to test it

Once in a while, rebuild the service on a clean machine using only the archive and the install script. Time it. The number you get is your real recovery time, and it is usually longer than expected the first time.