bind 9.4.3b2: too many open files

JINMEI Tatuya / 神明達哉 Jinmei_Tatuya at isc.org
Thu Jul 10 19:11:28 UTC 2008


At Thu, 10 Jul 2008 12:41:18 +0200,
Tom Mueller <t.mueller at strato-rz.de> wrote:

> yesterday we tested the beta version bind-9.4.3b2 and had some problems,
> so we had to switch back to the formerly used (insecure) version 9.4.2.
> The server is running under 'Linux 2.6.16.13-4-bigsmp athlon GNU/Linux'
> and ulimit -n shows '1024', fs.file-max was set up to 768000 for testing.
> In named.conf, recursive-clients is set to 5000.

> rndc status shows
>     recursive clients: 2195/4900/5000
> 
> The query rate is between 7.000 and 12.000 queries/sec.

This indicates that it's a pretty busy server, so it's possible that
all of the available 1024 ports are consumed.  Please increase the max
open files to 4096 and retry.
 
> netstat shows >900 UDP connections in state ESTABLISHED, but tcpdump
> doesn't show any traffic on  the  watched connections.

I suspect that queries sent over these 'connections' are simply not
responded.  It's not unusual and can happen for various reasons.
These non-responsible connections can potentially be the cause of 'Too
many open files', but I believe it will be fine in your case if you
increase the limit.

---
JINMEI, Tatuya
Internet Systems Consortium, Inc.


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