9.2.5 db causes high cpu? was: Re: BIND 9.2.5rc1 is now available.

Brad Knowles brad at stop.mail-abuse.org
Mon Feb 21 15:06:41 UTC 2005


At 3:47 PM +0100 2005-02-21, Stefan Schmidt wrote:

>  Well, if a dedicated recursing database backend and lookup routine would
>  significantly speed up the performance, then i think we should give it a try,
>  if the code would be not much different from what it looks now this can be a
>  configuration option just as well.

	I would be surprised if it helped all that much.  BIND8 and BIND9 
use in-memory database techniques that are pretty fast, and most of 
the differences between BIND9 as an authoritative-only server versus 
NSD are architectural.

	I believe that most of the benefit of using an external database 
storage mechanism with BIND9 will be operations management and 
tracking things that are not directly related to the DNS records 
themselves, but have more to do with large-scale database systems 
administration.  I don't think that performance will measurably 
improve, in fact I suspect that it will get worse, but the overall 
benefit for larger sites will be such that it would still be a win.

	If you want to greatly speed up the code, I think you're going to 
have to do another ground-up redesign and eliminate the architectural 
issues that are holding back BIND9.

>  I expect overall DNS query rates to rise midterm; keep in mind there are VoIP
>  (SIP) and E164 about to break through, not speaking of portable uses like
>  UMTS+EDGE mobile-IP or what kind of an DNS record inflation wide use of IPv6
>  could mean.

	Existing people are going to be generating more traffic, and more 
people are going to be coming online, and the traffic that will be 
generated will be larger and more complex.

	This is an exponential growth pattern that has been recognized 
for a while.  It wasn't "news" when I wrote about it for my LISA 2002 
invited talk (see 
<http://www.shub-internet.org/brad/papers/dnscomparison/>), and I 
don't see it changing any time soon.

>  Well it's an opensource project after all, how about interesting 
>more people -
>  and there are many bright ones still out there - to contribute to it?

	Brooks's "Mythical Man-Month" (see 
<http://en.wikipedia.org/wiki/The_Mythical_Man-Month>) teaches us 
that it's not just a matter of getting more people into the project.

	Our problem is getting more and better people into the project, 
and finding the funding to make that happen.  I think that the people 
at ISC already know who would be good people to bring in, if they 
could find the funding to make that happen.

	So, what people like you and I can do is work to try to find ways 
to get the necessary funding to ISC.

-- 
Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.


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