Tuning BIND servers - looking for operational experience

[Alan Clegg]

Greetings, BIND Operators!

As the maintainers of BIND, ISC is often approached by users of our
software asking about tuning for maximized performance.  To assist in
this, we are working on a number of knowledge base articles and we are
asking for community input.

The majority of "high-performance" operational experience within ISC
revolves around two very specialized endeavors, F-Root
(https://www.isc.org/f-root/) and the ISC Performance Lab
(https://www.isc.org/blogs/isc-performance-lab/).  While both of these
are "high performance" offerings, the reality is that they match a very
tiny demographic as far as operational usefulness goes.

What I would like to ask of the community is for real-world experience -
what did you do to "make BIND run better/faster/stronger"?  Have you
come across the "magic sysctl setting" that took your performance from
10kqps to 50kqps?  Did you find anything that was detrimental to your
performance that was surprising?  Any interesting "sweet spots" in
tunable settings that you found that might be useful to others?

If you want to create a thread here, that's fine or I'm more than
willing to take direct input via e-mail.  Please do note that the goal
of this is to create a document that assists the community-at-large and
your input will be used (with credit!) to that end.

Thanks!
AlanC