I am looking to redesign a mid size(corp) dns architecture and I have searched here and icann.org + google(of course) but I'm unable to find a best practice in regard to name server entries and zones/child nodes.
So here we go, say we have 10+ dns servers:
then we have say happy.example.com
and then we have:
A Records
- ns1.happy.example.com 222.222.222.222
- ns2.happy.example.com 333.333.333.333
- ns3.happy.example.com 444.444.444.444
- NS Records
- happy.example.com ns1.happy.example.com
- happy.example.com ns2.happy.example.com
- happy.example.com ns3.happy.example.com
THEN we have sad.example.com:
- A Records
- ns1.sad.example.com 222.222.222.222
- ns2.sad.example.com 333.333.333.333
- ns3.sad.example.com 444.444.444.444
- NS Records
- sad.example.com ns1.sad.example.com
- sad.example.com ns2.sad.example.com
- sad.example.com ns3.sad.example.com
My question is there any advantage to this?
Would it not be better to just do:
- A Record
- ns1.example.com 222.222.222.222
- ns2.example.com 333.333.333.333
- ns3.example.com 444.444.444.444
Then do:
- NS Records
- happy.example.com ns1.example.com
- happy.example.com ns2.example.com
- happy.example.com ns3.example.com
- sad.example.com ns1.example.com
- sad.example.com ns2.example.com
- sad.example.com ns3.example.com
My rule of thumb is 3-5 responders as optimal. Normally, I would prefer a responder to be a load balancer in front of at least two servers, but that's personal preference combined with hardware availability.
As to domain hierarchy, are your nameservers authoritative only? or recursive as well? How many clients? How many zones?
Regarding your specific question, unless your domains are absolutely massive, there should be no reason that the same servers can't be authoritative for both and yes, putting the nameservers in the higher level domain is better. Otherwise you're going to have to include GLUE records as well.