[dns-operations] BIND performance difference between RHEL 6.4 and FreeBSD 7

Evan Hunt each at isc.org
Tue Apr 22 22:05:53 UTC 2014

On Tue, Apr 22, 2014 at 02:40:08PM -0700, Shawn Zhou wrote:
> Our performance tests show that ISC BIND (authoritative only setup)
> doesn't perform well on RHEL 6.4 in comparison with FreeBSD
> 7:?bind_perf.png

You didn't specify which version of BIND, but I know that BIND 9.9 and
higher, when running on Linux, is sensitive to the number of threads
listening for incoming UDP connections. You can adjust this via the -U
command line option: If you have 8 processors, I'd try it at -U 4, -U 5,
-U 6 and -U 7 and see where the peak performance was found.

Older linux kernels had a problematic UDP stack that caused a big
performance drop relative to BSD or Solaris, essentially reducing it
to single-thread performance.  I believe all the major Linux distributions
have switched to lockless UDP by now, but it might be worth checking out.

Evan Hunt -- each at isc.org
Internet Systems Consortium, Inc.

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