Listen queue overflow

[Mike Tancsa]

On 8/1/2013 5:09 PM, Andre Oppermann wrote:
> On 01.08.2013 16:47, Mike Tancsa wrote:
>> After upgrading from a RELENG9 kernel from June 18th to July 27th, I am
>> seeing this odd new message.  Is this a new bug, or just a new
>> diagnostic message ? I am guessing it happened after r253035 ?
>>
>>
>> sonewconn: pcb 0xfffffe001ac76930: Listen queue overflow: 8 already in
>> queue awaiting acceptance
> 
> This message tells you that your daemon listening on that protocol control
> block isn't keeping up with accepting new messages and each time one of
> these
> lines appears the kernel had to reject a connection attempt (RST)
> because of
> too many connections already waiting in the listen queue.
> 
> The only unusual thing here is the low listen queue size of only 8
> connection
> attempts.  The default kernel value is about 20 times as many.  Have you or
> your application changed it manually?
> 

Not knowingly.  The odd thing is that happened at exactly 9am 2 days in
a row. I dont schedule anything on the box for that time

Jul 29 09:00:00 backup3 kernel: sonewconn: pcb 0xfffffe001ac76930:
Listen queue overflow: 8 already in queue awaiting acceptance
Jul 29 09:00:00 backup3 last message repeated 3 times
Jul 30 09:00:00 backup3 kernel: sonewconn: pcb 0xfffffe001ac76930:
Listen queue overflow: 8 already in queue awaiting acceptance
Jul 30 09:00:00 backup3 last message repeated 5 times

Seems a bit coincidental. Box is AMD64 9.2-BETA2 FreeBSD 9.2-BETA2 #0
r253707:

Its a backup server. It does outbound rsync, but that wasnt running at
the times of the errors. No unusual inbound traffic at those times. Its
also running radium, to connect to a number of argus sensors, but those
are outbound connections.

/etc/sysctl.conf

net.inet.tcp.recvbuf_max=16777216
net.inet.tcp.recvspace=131072
net.inet.tcp.sendbuf_max=16777216
net.inet.tcp.sendspace=32768
net.inet.udp.recvspace=65536
kern.ipc.somaxconn=1024
net.inet.ip.redirect=0
net.inet.ip.intr_queue_maxlen=4096
net.route.netisr_maxqlen=1024
kern.ipc.nmbclusters=262144
vfs.ufs.dirhash_maxmem=8097152
vfs.read_min=2

As well as nfs, it also runs samba for windows backups.

	---Mike

-- 
-------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada   http://www.tancsa.com/