How to free up some space in DirectAdmin?

You can do the following to free up some space:

cd /usr/local/directadmin/custombuild
rm -f *.tar.gz
rm -f *.tgz
rm -rf mysql
rm -rf /usr/local/directadmin/scripts/packages/*

If you do not need MySQL backups, you can also execute:

rm -rf /usr/local/directadmin/custombuild/mysql_backups