[Pdns-users] powerdns auth and recursor hardware specs

[Eugene Pefti]

What is the value your max-cache-entries set to, Brendan?
I set it to 40000 looking at the graph "Cache sizes". The curve for cache
sizes is slowly rising above 40k. But I would be worried because there are
about 400 MB free of RAM
Playing with recursive-cache-ttl seems to me more worthwhile too. I set it
to 600 for now to see it improves anything.
And finally thanks for a hint about allow-recursion-override, I didn't know
that. I'll try that too.

Apart from this I'll try to experiment with key_buffer as it was proposed by
Brad Dameron earlier today. Thanks to Brad as well

Eugene

-----Original Message-----
From: pdns-users-bounces at mailman.powerdns.com
[mailto:pdns-users-bounces at mailman.powerdns.com] On Behalf Of Brendan Oakley
Sent: Wednesday, April 30, 2008 12:32 PM
To: pdns-users at mailman.powerdns.com
Subject: Re: [Pdns-users] powerdns auth and recursor hardware specs

Hi,

I can't really speak to the specifics of your setup, but some
generalities based on ours.

On Tue, Apr 29, 2008 at 10:39 PM, Eugene Pefti <eugenep at w3media.net> wrote:
> I think I miss something here. Can somebody give an example of hardware
>  specs for the authoritative server with recursor running? I run it on
CentOS
>  5 with 2.6 GHz P4 and 1 GB of RAM. There's MySQL backend and about 700
>  domains hosted. Still the server experiences periods of slowness. I have
>  already presented a link to rrd graphs for the server. Do I have to run a
>  separate box with the recursor?

I have found that when running the authoritative server with the
recursor, it is necessary to set a limit on max-cache-entries. By
default, it has no limit, and that can potentially cause too much
memory usage depending on load. Also, increasing the
recursive-cache-ttl in pdns.conf helped a lot to reduce the load on
the recursor. It took some experimenting with these and other settings
to get it all fully optimized for our network.

I was surprised that allow-recursion-override=yes needed to be set,
it's no by default, so that some authoritative queries go to the
recursor. I don't get that.

I hope that's helpful.
Brendan
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