BIND 9.x caching Performance under heavy loads

Rick Jones foo at bar.baz.invalid
Thu Mar 3 18:52:03 UTC 2005

Srini Avirneni <avirsri at> wrote:
> Yes, it is a suprise. Its a surprise to see Bind as a process, peak
> at 25% CPU day 1. Then, Day 2, peak climbs to over 50%. Load has not
> changed.

> By day 3, CPU will exceed 75% and Bind will no longer respond in
> a meaning full way (< 500 queries/sec). This is on very fast
> hardware.

> This was with peak query rates of 2500/sec ranging down to 1200/sec.

> As load increased, the CPU time ran away quicker. One would expect
> that a Bind server that runs at 25% CPU during peak, would within a
> few points, operate as such continually, and scale somewhat
> linearly.

Clearly we need to find some way to gather profiles of the process
each day to see which routines start consuming more time.  If this
were PA-RISC or Itanium I'd suggest either Prospect for PA-RISC
( or Caliper for Itanium
( or perhaps q-syscollect for Itanium 2.6
linux (

The important thing is to find a tool for your platform that can
attach to a running process and get the profile - clearly having to
stop and restart the process is going to alther the behaviour, and I
we cannot just start it profiled and leave it that way for N days -
too much chance of counter overflow and the effect of previous days
may not be fully overcome.

rick jones
portable adj, code that compiles under more than one compiler
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to raj in  but NOT BOTH...

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