74 hours till next "No Buffer Space Available" reboot ...

[Daniel Eischen]

On Sat, 14 Apr 2007, Marc G. Fournier wrote:

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> - --On Sunday, April 08, 2007 23:04:42 -0400 Dave <dmehler26 at woh.rr.com> wrote:
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>> Hello,
>>     This is what i get for catching this late. Can you describe your
>> situation? I've got a server, router actually running 6.1-p6 i believe, and
>> lately it's been doing this stop. I can't be any more specific than that,
>> because that's all i know. The box just goes unresponsive, i can get a login
>> prompt on the console, but it's unresponsive. I have to reboot it. This has
>> occurred twice now and i'm starting to get concerned. I've ruled out ram, i
>> recently replaced it's ram for an unrelated reason so i don't think that's
>> it. If your situation is similar can you let me know what you tried?
>
> This is a different situation, I think ... first, I'm running 6.2-STABLE, as of
> about last week, so a much newer kernel then you are running ... and in my
> case, at least, I can still login to the machine using ssh and force a reboot
> remotely ... it doesn't seem to be a 'solid hang' ... if I were to hazard a
> guess as to what it "feels like" ... it feels like the network interface
> "buffer" has filled up, but isn't being released properly ... almost like a
> memory leak, but on the network ... if I leave it long enough, it will
> eventually require a tech to power cycle it, but if I catch it early enough, I
> can still get in to do a reboot ...
>
> But ... that said ... when you say "'get a login prompt on the console, but
> it's unresponse" ... do you mean that you can actually type in a userid, and
> possibly passwd, but after that it just hangs?

I will just add that I get this on an old 4-stable router
box (for years).  It is on an sf interface and I _thought_
it was due to a flaky hub.  I got the "sendto: no buffer
space avail" message on the incoming/outgoing interface
to the router that was doing NAT and ipfw to our internal
LANs.  I resorted to writing a cron job that would try
to ping the router at the other end of the sf interface
and do an 'ifconfig sf0 down; ifconfig sf0 up' whenever
the router at the other end could not be ping'd.  Something
like this:

   if ping -c 2 remote-router > /dev/null; then
     /usr/bin/true
   else
     /sbin/ifconfig sf0 down
     /bin/sleep 1
     /sbin/ifconfig sf0 up
   fi

This router is running 4.11.  Without the cronjob, the
network would fail every week or two.  I gave up trying
to figure out what the real problem was.

-- 
DE