Using a low TTL to enable a fail-over cluster?

[Barry Margolin]

In article <a7fs1h$irb at pub3.rc.vix.com>, Nate Campi  <nate at campin.net> wrote:
>
>On Fri, Mar 22, 2002 at 05:26:58PM +0000, phn at icke-reklam.ipsec.nu wrote:
>> 
>> Jakob Bak <Jakob at bak.com> wrote:
>> 
>> > 2) How much traffic does a secondary DNS get when the primary seem to be
>> > running perfectly?
>> >    (0% or ?%)
>> 
>> 2 servers would get 50% each, 3 servers 33% etc. There is no
>> distinction between "primary" or "secondary" they are all
>> "nameservers" and they are all consulted in "unpredictable order"
>
>In reality, BIND and it's usage of RTT to find and use the fastest
>responding nameserver makes this incorrect. Since most of the
>nameservers out there are BIND, this has a visible effect on the
>distribution of queries to most nameservers.

Only if the response times are significantly different.  It uses fuzzy
comparisons of the RTT's, so if all the servers respond within a few
percent of each other, they'll be treated equally.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
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