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Date:      Mon, 27 Mar 2006 13:15:01 -0500
From:      "Michael W. Lucas" <mwlucas@blackhelicopters.org>
To:        Maxim Konovalov <maxim@macomnet.ru>
Cc:        hackers@freebsd.org
Subject:   Re: syslogd not draining
Message-ID:  <20060327181501.GA58448@bewilderbeast.blackhelicopters.org>
In-Reply-To: <20060327214209.U87890@mp2.macomnet.net>
References:  <20060327160130.GA57689@bewilderbeast.blackhelicopters.org> <20F3E06D-5727-4531-A81B-DF64765D1564@SARENET.ES> <20060327173841.GA58274@bewilderbeast.blackhelicopters.org> <20060327214209.U87890@mp2.macomnet.net>

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On Mon, Mar 27, 2006 at 10:01:42PM +0400, Maxim Konovalov wrote:
> On Mon, 27 Mar 2006, 12:38-0500, Michael W. Lucas wrote:
> 
> > On Mon, Mar 27, 2006 at 06:18:50PM +0200, Borja Marcos wrote:
> > > >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.
> 
> That's not enough.  You need to teach syslogd to use this new value.

I don't see this in syslogd(8); I presume it require source hacking?

> > > >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                *.*
> > >
> > > Are you using a serial console? I had similar problems in the past
> > > due to the serial port flow control.
> >
> > I've disabled syslog to the console, writing instead to
> > /var/log/console.log.
> >
> > Moments after doing that, the problem reoccured.  Thanks, Borja, but
> > no success.  :-(
> >
> > Any other suggestions, folks?
> 
> What's the incoming udp datagrams rate?
> 
> netstat -sp udp | grep 'datagrams received'; sleep 10; \
> netstat -sp udp | grep 'datagrams received'

        158169 dropped due to full socket buffers
        2467251 datagrams received
	sleeping...
        158903 dropped due to full socket buffers
        2468299 datagrams received

> How much cpu time does syslogd use?

Not much.  ps -ax | grep syslog gives:

 4317  ??  Ss     0:01.60 /usr/sbin/syslogd -l /var/run/log -l /var/named/var/run/log

Process has been running for about five minutes at that point.

Another point that might be of interest:

ns1/etc;rc.d/syslogd restart
Stopping syslogd.
Waiting for PIDS: 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317, 4317
Starting syslogd.

==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



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