Backups are simple.

Dump your database into a file + create a compressed tarball of your database file + any code files.

Or, if you require hot sparing, run your system in an LXD container + do periodic rsyncs from container to a container on another machine. Then, say once a day, stop the production container + do another rsync to ensure all memory buffers are flushed (database is consistent), then restart production container.

You can also use database replication, so you only lose the last transaction if your production site goes down.

If you're running hot spares, if your production site goes down, you just change your IP to point to your spare + you're back online.