[lug] Clustering for Load-Balancing and Fault-Tolerance??

[Dave Anselmi]

Shannon Johnston wrote:

> Hello all!
> I'm looking for opinions here...
> I need load-balancing, fault-tolerant DNS servers. (Not load-balancing
> for http, but distributing DN resolution requests.) I've never worked
> with clusters before so I would like to know where a good starting point
> would be, and if anybody has any suggestions as to what to use.

Do you really?  I suppose you could look at the sites mentioned and put a
load balancing machine in front of several DNS servers.

When you list several name servers as authoritative for a domain, I would
guess that other name servers will pick between them at random.  You don't
need any session sharing type fault tolerance because DNS only uses one
packet each direction.

The only thing clustering will buy you is that all the name servers could
share one IP, so if one goes down there's no delay from asking it for a
lookup.  Unless you're talking about load balancing recursive requests
(i.e., from resolver clients rather than name servers).

I'm curious what setup you have and why you think clustering is the way to
go.

Dave