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

Stefan Schmidt zaphodb--bind at zaphods.net
Sat Feb 19 22:42:33 UTC 2005


On Thu, Feb 17, 2005 at 06:18:02PM +0100, sthaug at nethelp.no wrote:
> Our problems with BIND 9 as a recursive name server:
> 
> - Higher CPU usage than BIND 8 (around 50% higher in our measurements).
My curve seems to have stabilized now and it backs up your 50% higher than
bind8 measurement. -> http://zaphods.net/~zaphodb/cpuwfrell2.gif
(My Webserver is currently shutting down 5m after daily cron - since i enabled
webdav - did not yet figure out why it does, but its in a friends nagios now,
so try again if you experienced problems connecting.)

> - Most important: We have had repeated cases of BIND 9 failing when the
> cache reaches a size of around 250 Mbps (which is still well below any
> datasize limit for the named process). "Failing" means that some queries
> are simply never answered. Starting the named process again makes the
> problem disappear (until the cache grows big again).
I did not experience that with 3 other machines i am running bind9 on. Only
one of them uses 291m virt 258m res but the machine the graph is from is
recursing for our DSL customers and currently running at 623m virt 588m res as
top states. I have set max-cache-size 700M; there but previous bind9
experiments show that it does not really care about when it breaches this
limit. On Linux that is capability module loaded. Sorry ISC.

I had a smokeping running that queries for dns milliseconds with dig but it
seems the module made it far to unstable to get proper images - perhaps i'll
have some 'dns packet-loss' graphs for you as well soon.

> We have had the Nominum Caching Name Server (CNS) on trial, and would
> *really* prefer to use this, if the price was better. It works just
> great, and for us it was an order of magnitude more efficient than BIND
> 9. However, the price was high enough that we concluded BIND 8 plus
> throwing more hardware at the problem was a better solution.
> (If you can afford CNS, it's a wonderful product and I recommend it
> highly.)
Would you mind telling me the price so that i do not even have to try it and
feel it would be the better solution? ;)

	Stefan Schmidt, Hostmaster freenet Cityline GmbH (AS5430)
-- 
"IRC can be far more than just multiplayer vi"


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