Does many dns servers around the world improve the response time?

[Kevin Darcy]

MontyRee wrote:
> Hello, list.
>
>
> I have some questions about RTT(Round Trip Time) related.
> please let me know. 
>
>
> -.I have operated cache only bind dns server.
>   but, where can I find RTT information at my DNS Server?
>   
If you have a sufficiently-modern version of BIND, you can dump its 
database (via rndc dumpdb), and in the dump file there will be a section 
that looks like this:
;
; Address database dump
;
; ns6.mesdns.net [v4 TTL 3295] [v6 TTL 3295] [v4 success] [v6 nxrrset]
; 66.46.181.244 [srtt 31] [flags 00000000]
; ns3.radicalties.com [v4 TTL 72299] [v4 success] [v6 unexpected]
; 64.38.195.231 [srtt 55050] [flags 00000008] [ttl -524]

, and, typically many more entries.

> -. If I operating the global web site, is it better to setup lots of dns servers as many as possible(max 13)
>    around the world to improve the response time?
>  
>   
It might help a bit, yes, but typically in a global-website context, the 
main delay consists of fetching the actual web content, with the DNS 
lookup being only a small fraction of the time. You might want to focus 
on CDN (Content Delivery Network) technology more than trying to 
optimize your DNS lookups. Sometimes DNS and CDN technologies are rolled 
into one package anyway (at least, I know this is true of some of 
Akamai's offerings), so you may end up not having much flexibility on 
the DNS side of things anyway.

- Kevin