BIND 9 scaling

[Rick Jones]

Phill Wood <phill.wood at gmail.com> wrote:
> I've just subbed to the list. We've been using BIND for some years
> now, currently on versions 9.2.3 and 9.2.4.

> We're master for a relatively small number of zones (~ 1500) and
> provide a caching nameserver service as well. I've never encountered
> any performance issues myself but my management are asking what the
> limits might be.

> We served 6,000,000 requests yesterday using one CPU of a dual-CPU
> Sparc box (running with -n 1 due to threading bug in 9.2.3). Maximum
> load average was 0.46.

> Can I say, therefore, that we will be able to serve 12,000,000
> requests easily and then performance may wane? And at what level of
> hits would we start to suffer?

You could say it, but I would not count on it being true unless and
until you actually measured it or at least had a bit more supporting
data.

Load average is one thing.

CPU utilization is another.

Sometimes they relate, sometimes not.

What was the CPU utilization of the one CPU running named when you
served 6 million requests in a day?  Particularly at peak?  

BTW, for "things networked" it has been my experience (via netperf)
that one cannot entirely trust the output of mpstat - it misses time
spent processing interrupts and when networking is involved, there are
generally more than a few interrupts...  Believe it if it says 100%
utilized, believe it less and less as it reports lower CPU util -
particularly if there is a non-trivial number of interrupts being
reported. 

rick jones
ftp://ftp.cup.hp.com/dist/networking/briefs/
-- 
oxymoron n, commuter in a gas-guzzling luxury SUV with an American flag
these opinions are mine, all mine; HP might not want them anyway... :)
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