in case you have 10 servers each running all the services for domains hosted on it, will you consider spliting them ? and also how you split them ?

for the above case, will you split them by
1 dns server, 1 mail server, 4 httpd servers, 3 database servers, 1 offsite back up server?

or any better config?

PS. all the 10 servers are hosting websites using general aaplications and no other not-so-common stuff

thanks

Well,

If you are running a very high traffic server, then splitting services reduces server load, and increase performance..

Your config is fine, but you will be having one server for only DNS??

You better share the DNS server with something else, lets say mail server, or SQL server... otherwise, rent a VPS to do the DNS job.

for large enough sites/hosting operations, having separate physical name servers is a good thing(tm). I'd personally recomend having 2 physical name servers. Just in case...