Re: failover and dns

[Doug Hughes <Doug.Hughes () Eng Auburn EDU>]

> It strikes me that a round-robin DNS might serve you well here. To my
> knowledge, round-robin DNS won't handle "if A fails then try B" -- it will
> cycle through all 'X' datacenters/sites, distributing the connections
> amoung them. In this scenario, if a particular site is not available, the
> user would have to try again later and most likely (with a short TTL) get
> sent to another site.
>
> Are there round-robin DNS implementations that perform "aliveness" tests
> and drops unavailable sites out of the round-robin?

Well, the most famous would be lbnamed published in LISA IX

> From http://www.usenix.org/

 Summary: lbnamed: A Load Balancing Name Server in Perl. This paper
       discusses an attempt to solve that problem using a load balancing 
       name server. This name server also has the ability to serve other
       dynamic information as well, such as /etc/passwd information (a la
       Hesiod [2]). 
--
____________________________________________________________________________
Doug Hughes                                     Engineering Network Services
System/Net Admin                                Auburn University
                        doug () eng auburn edu