We have a straightforward setup asterisk server.
Can you tell which folders to backup to ensure that we can quickly start up a new server if something goes wrong with the old?
Basically /etc/asterisk - this contains the configuration files. If you have something like Voicemail and want to keep the recorded messages as well - look in /var/spool/asterisk
/etc/asterisk
/var/lib/asterisk
and
/var/spool/asterisk
would be my recommendation. That way you have any call recordings, prompt files, music on hold, the astdb database, etc.
Files to consider for backup
Asterisk configuration
Asterisk internal DB
Other database used by Asterisk
Asterisk logs and reports