I put this page together just so I won't spam the board anymore begging
for help..lol
http://bobhoffman.com/vmissue.html

This shows a working effort of bonded eths, bridged into a vm, and a few
other things.
The only missing thing is something on the host that ends up putting the
VM internet
connection into some kind of limbo.

Whether it is hardware related, bug related, libvirt nat related, I
don't know.
I will only post here on this issue again if it ever gets solved.
At this point the server is a no go and getting shelved until I can find
a tech
that knows this stuff and can fix it.

right now: unsolvable.

I may just put some websites on the host computer until I can find a
reliable way of
keeping the virtual guest connection 100% up.

Hope this helps someone wanting to bridge or bond.

bob
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I have no idea if this is the source of your problem (I wasn't using
bonded interfaces), but it's sufficiently similar that you might
want to try it.

I had a lot of problems with the network stack on VMs, both under
VMWare ESXi and Xen where the network would just go numb. After a
lot of splunking I determined that it seemed to be related to
faulty TCP segment offload. Generally speaking, between the VM,
the virtual NICs, the hypervisor/host, and the physical network card,
some levels figured that they'd offload segmentation handling to
a lower layer, the lower layer wasn't doing it, and the upper layer
thought that it was.

Under low network load everything seemed fine but as the network
got pushed things would blow up and go numb.

Turning off TSO in the VM seemed to do the trick, although I think
in the Xen case I turned it off in the host as well.

The basic command is: /sbin/ethtool -K ethX tso off

While I had the above command in rc.local, I would also run the
attached script in /etc/cron.hourly as there were some circumstances
where tso would get reenabled.

Good luck

Devin
--
Some people are like Slinkies: Not really good for anything, but you can't
help but smile when you see one tumble the stairs.
- Anonymous
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Devin Reade <gdr@gno.org> wrote:

[...]
> While I had the above command in rc.local, I would also run the
> attached script in /etc/cron.hourly as there were some circumstances
> where tso would get reenabled.

And in case attachments get stripped on the mailing list, you
can also get the script here:

<ftp://ftp.gno.org/pub/tools/force-tso>

Devin
--
Some people are like Slinkies: Not really good for anything, but you can't
help but smile when you see one tumble the stairs.
- Anonymous

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On 02/06/2012 09:28 PM, Bob Hoffman wrote:
> I put this page together just so I won't spam the board anymore begging
> for help..lol
> http://bobhoffman.com/vmissue.html

You're using bonding mode 0, which may not work when attached to a
bridge. Try changing to mode 1 and playing with the cables. If every-
thing works with mode 1, you've got an idea on where to focus.

As far as active/active bonding modes go, I know that mode 4 (LACP) is
supposed to work, but that requires support on the switch(es).

--
================================================== ======================
Ian Pilcher arequipeno@gmail.com
"If you're going to shift my paradigm ... at least buy me dinner first."
================================================== ======================

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Although it was written in the context of Xen, you might also want to have a
look at the netloop nloopbacks parameter as described in
<http://www.novell.com/communities/node/4094/xen-network-bridges-explained-with-troubleshooting-notes>.
On a Xen cluster with 3 physical interfaces per node I had to increase
that parameter to keep interfaces from going numb.

I don't know how this translates to the libvirt/kvm world.

Devin
--
Some people are like Slinkies: Not really good for anything, but you can't
help but smile when you see one tumble the stairs.
- Anonymous

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