[Unbound-users] patch implementing round robin rrsets

Felix Schueren felix.schueren at hosteurope.de
Wed Mar 7 17:27:08 UTC 2012


actually, I feel that DNS-based "load balancing" or "load distribution"
when relying on RRset randomization is the poorest choice you can make -
you have no control at all over distribution of the traffic, which means
that a single system must be able to take the full load anyway, plus you
end up with downtime of at least RRset TTL, or minimum cache TTL in some
cases. Even with randomization in Unbound these problems do not get
fixed - in my opinion you're fixing the wrong side of the problem. DNS
by itself was never meant for loadbalancing, and trying to retrofit it
in, you'll always come to a point where you realize that you should have
used loadbalancers or some other redundancy/failover mechanism from the

Also, thousands of clients is not really a figure that shows how big or
small the impact of the additional CPU required might be on a properly
loaded setup - how many queries per second are you doing with your
setup? We're currently sitting at approx 30,000 queries per second.

Wouter, if you bring this randomization into mainline, please make it
configurable, as in my opinion this is only useful for very few
specialized environments, most notably probably resource-constrained
institutions that are forced to use dns-based loadbalancing.

Kind regards,


Felix Schüren
Head of Network

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