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 13:45:17 UTC 2005

At 1:11 PM +0100 2005-02-21, Stefan Schmidt wrote:

>  I do too. I did not want to abolish _any_ BIND9 feature or default behaviour,
>  i just merely wanted to suggest that future BIND9 releases should have more
>  knobs to fiddle with either at compiletime or via configuration options.

	More knobs to twiddle for configuration options would be a good 
thing.  I'm not sure how much work should go into more knobs to 
twiddle at compile-time.

>  Something like the possibility to change the underlying database backend, for
>  example to Berkeley DB hash or btree, the possibility to optimize the lookup
>  function for authorative or recursive-only mode or just to make the decision
>  whether to have views or not.

	I don't think I'd ever leave out the code to implement views.  I 
consider that to be a fundamental part of BIND9 and should never be 
optional.  I also don't think that compile-time options for 
authoritative-only versus recursive-only mode would be a good idea -- 
keep those as configuration options.

	The use of Berkeley DB or other alternative database back-end, I 
think is something I would also prefer to be largely controlled 
through configuration options, but obviously you can't pre-compile 
with headers and libraries pre-linked for all possible database 

>  I did not yet reimplement the DNS-smokeping so i do not know 
>whether or not it
>  is slower but it seems to get a slightly higher query-rate from the
>  loadbalancer and eats up just as much user cpu as the two BIND8 processes on
>  the other machine. Generally i would expect a singletasking application to
>  answer queries more quickly than when it is threaded.

	It would be interesting to retry the DNS-smokeping to see what 
happens with the new configuration.

>  There should be more people on this list that are familiar with the internals
>  of BIND9 - i really would like to hear from you guys. Any Nominum employees
>  willing/able to give a short statement on how they did it with CNS maybe? ;)

	I think the Nominum guys are going to be under NDA for the work 
they did.  However, note that the original implementation of BIND9 
was done by Nominum under the guidance of ISC, with a lot of input 
from a variety of industry supporters.  My understanding is that most 
of that team was then used to do the ground-up re-write for ANS and 

	I understand that a significant number of those people are no 
longer working at Nominum, so if you could find a way to get them to 
contribute work to BIND9, then I think we might be able to take 
advantage of their experience.  However, these people do have to put 
bread on the table, and not knowing where they are working today, I'd 
have to say that a significant amount of funding would have to be 
channeled through ISC to bring these people back into the process.

	Otherwise, the people who used to work at Nominum and have been 
transferred back to ISC (and work on BIND9) is very limited, and ISC 
just doesn't have the kinds of resources to fund work on BIND9 that 
Nominum was able to put together for ANS and CNS.

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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