[ovirt-users] Ovirt causing strange network issues?

[Colin Coe]

Spanning Tree Protocol.

Make sure the /etc/sysconfig/network-scripts/ifcfg-eth0 (or whatever) does
not have an STP=yes line.

CC

On 3 Oct. 2017 19:11, "Derek Atkins" <derek at ihtfp.com> wrote:

> I'm sorry. What is STP?
> And how do I turn that off?
>
> -derek
> Sent using my mobile device. Please excuse any typos.
>
> On October 2, 2017 7:41:15 PM Colin Coe <colin.coe at gmail.com> wrote:
>
>> Hi
>>
>> We saw something very similar to this a couple of years ago.  In our
>> case, it was caused by STP being enabled on our hypervisors.
>>
>> HTH
>>
>>
>>
>> On 3 Oct. 2017 04:56, "Derek Atkins" <derek at ihtfp.com> wrote:
>>
>>> Hi,
>>>
>>> I'm at my wits end so I'm tossing this here in the hopes that SOMEONE
>>> will be able to help me.
>>>
>>> tl;dr: Ovirt is doing something on my network that is causing my fiber
>>> modem to go from 3-5ms to 300-1000+ms round trip times.  I know it's
>>> ovirt because when I unplug ovirt from my network the issue goes away;
>>> when I plug it back in, the issue recurs.
>>>
>>> Long version:
>>>
>>> I've been running Ovirt 4.0.6 happily on CentOS 7.3 for several months
>>> on a single host machine. Indeed, the host had an uptime of 200+ days
>>> and was working great until approximately midnight, September 21/22
>>> (just over a week ago).  I was on an airplane halfway across the
>>> Atlantic at that time, so it wasn't anything I did.
>>>
>>> My network is configured as:
>>>
>>>   fiber modem <-> edgerouter <-> switch <-> everything else
>>>
>>> ovirt is living in the "everything else" area.
>>>
>>> When I sit with a laptop connected to either the everything else range
>>> or even directly connected to the fiber modem, I run 'mtr' and see
>>> network times (starting at the fiber modem) that bounce all over the
>>> place.  When I unplug ovirt I see consistent 3-5ms times.  Plug it back
>>> in, voom, back up to badness.
>>>
>>> I've spent several hours plugging and unplugging different devices
>>> trying to isolate the issue.  The only "device" that has any effect is
>>> my ovirt box.
>>>
>>> I have tried to debug this in several ways, but really the only thing
>>> that seems to have helped at all is shutting down all the VMs and the
>>> hosted engine.  Once nothing else is running (but the host itself), only
>>> then does the network seem to return to normal.
>>>
>>> I'm really at my wits end on this; I have no idea what is causing this
>>> or what might have changed to cause the issue right at that time.  I
>>> also can't imagine what ovirt is doing over the network that could cause
>>> the modem, two physical hops away, to lose its mind in this way.  But my
>>> experiementation is definitely showing a direct correlation.
>>>
>>> Help!!
>>>
>>> -derek
>>>
>>> --
>>>        Derek Atkins                 617-623-3745 <(617)%20623-3745>
>>>        derek at ihtfp.com             www.ihtfp.com
>>>        Computer and Internet Security Consultant
>>> _______________________________________________
>>> Users mailing list
>>> Users at ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/users
>>>
>>
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