I've been managing 40ish installs of Directadmin since a year now, and although the control panel has a great backup system built in for users and resellers, we always make a backup every night to move it to an external server over the 2nd network interface..

Take into account that you'll need a current tar binary, else you'll need to split up the /home backup dir alphabetically (the older tar files are limited to 4GB)

Make a backup2 user (backup can't be used due it seeing that as a system accountname) with an unlimited bandwith and diskspace package under the admin user

#!/bin/bash

cd /home/backup2
rm -f *.tar.gz

tar -zcvf SERVERNAME_SYSTEM.tar.gz /etc/* /root/*
tar -zcvf SERVERNAME.tar.gz /home/* --exclude backup2
tar -zcvf SERVERNAME_MySQL.tar.gz /var/lib/mysql/*
tar -zcvf SERVERNAME_DIRADMIN.tar.gz /usr/local/directadmin/*
tar -zcvf SERVERNAME_DNS.tar.gz /var/named/*
tar -zcvf SERVERNAME_MAIL.tar.gz /var/spool/*

Now you'll have all needed packages to restore Directadmin on a server in case something would go wrong, upload them on an external backup server each night to make it secure..., and put the script in the cron ('crontab -e' as root, and enter something along the line: 0 2 * * * /home/backup2/backup.scp to run it each night at 2am)