Now we host about 100,000 domains and they are all using the same DNS servers (cPanel cluster system)
So now I checked our /etc/named.conf files.. and these are HUUUGE.. If you try to start/restart named service it takes 5 minutes to load all zones. It is also taking about 30% CPU and 35% of ram when running even on dual core server..
Any ideas how could we optimise named configuration ? Maybe it is something like mod_vhost_alias for Apache just for bind service ?
You could look at using NSD instead of BIND, assuming these are authoritative only servers for your domains, rather than used for outbound DNS queries from your servers as well. NSD has a compatible file syntax with bind but precompiles the database and is far more efficient in terms of speed/resources consumed.