Can DNS Round Robin be fault tolerant?

[Dave Sparro]

On 10 Jan 2006 08:52:07 -0800, RaysOfSearch <RayMan6 at gmail.com> wrote:
> I am trying to use DNS round robin for load balancing multiple web
> servers. I have read that there are some problems with this approach
> however, specially related to fault tolerance and session maintenance.
> By fault tolerance I mean if a web server is down, the DNS server has
> no way of detecting this and will still send every nth request to the
> dead server. I
{snip}
Those are the type of statements that make DNS administrators uneasy
when you start to talk about using DNS for load balancing.  DNS does
nothing but answer queries.  It's up to the user's application / OS /
name servers to interpret the answers, and take action based on them. 
DNS doesn't send http requests anywhere, web browsers do..

The fact that like 90% of the world is using IE on Windows lets you
get away with making some assumptions, but the behavior is not
universal.  Most of the DNS based load balancing/fail over scenarios
discussed will work to some degree.  Just don't confuse them with High
Availability.