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Date: Mon, 27 Mar 2006 11:01:30 -0500
From: "Michael W. Lucas" <mwlucas@blackhelicopters.org>
To: hackers@freebsd.org
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Subject: syslogd not draining
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Hi,

I've got a machine running syslogd, DNS, DHCP, flow-capture, and other
assorted UDP-loving programs.  Occasionally, they all stop working.
The machine has been up for a couple of hours now, and I see:

ns1/etc;netstat -s | grep full
Warning: sysctl(net.inet6.ip6.rip6stats): No such file or directory
        122066 dropped due to full socket buffers
ns1/etc;

I've doubled kern.ipc.maxsockbuf a couple of times now, and yet it
still happens.

After some help from questions@, I'm pretty sure that the culprit is
syslogd.

udp4       0      0  *.67                   *.*                    
udp4   43414      0  *.514                  *.*                    
udp4       0      0  *.49661                *.*                

Things run perfectly for a while, and then we suddenly stop answering
UDP requests.  We continue not answering UDP requests until I restart
syslogd.

syslogd -d didn't give anything interesting.

I'm now running syslogd -n, to see if that helps.  I'm also restarting
syslogd every fifteen minutes, to ensure that the problem can last no
longer than 14 minutes.  :-)

Anyone interested in why syslogd is not draining the queue?

Thanks,
==ml


-- 
Michael W. Lucas	mwlucas@FreeBSD.org, mwlucas@BlackHelicopters.org
		http://www.BlackHelicopters.org/~mwlucas/

"The cloak of anonymity protects me from the nuisance of caring." -Non Sequitur