Thanks for the info.
So do the following steps:
Make backup: 1. stop service, 2. make backup from /var/lib/repeat server directory, 3. start service.
Restore system: 1. reinstall repeater server, 2. stop service, 3. restore backup
Okay, so far clear. After that the system should be back with all gcodes, printers, logs etc.
But, if this is to be done automatically, there is no check at the beginning if there is a print job running. Is there a simple way that I can query via script if a print job is running? Is there any file that is only there, a tmp file, when a just any de printer has a print job?