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On Wed, Jun 21, 2017 at 02:39:23AM -0700, Kevin Benton wrote:
:Are there any events going on during these outages that would cause
:reprogramming by the Neutron agent? (e.g. port updates) If not, it's likely
:an OVS issue and you might want to cross-post to the ovs-discuss mailing
:list.

Guess I'll have to wander deeper into OVS land.

No agent updates and nothing in ovs logs (at INFO), flipping to Debug
and there's so many messages they get dropped:

017-06-21T15:15:36.972Z|00794|dpif(handler12)|DBG|Dropped 35 log messages in last 0 seconds (most recently, 0 seconds ago) due to excessive rate

/me wanders over to ovs-discuss

Thanks,
-Jon

:Can you check the vswitch logs during the packet loss to see if there are
:any messages indicating a reason? If that doesn't show anything and it can
:be reliably reproduced, it might be worth increasing the logging for the
:vswitch to debug.
:
:
:
:On Tue, Jun 20, 2017 at 12:36 PM, Jonathan Proulx <jon at csail.mit.edu> wrote:
:
:> Hi All,
:>
:> I have a very busy VM (well one of my users does I don't have access
:> but do have cooperative and copentent admin to interact with on th
:> eother end).
:>
:> At peak times it *sometimes* misses packets.  I've been didding in for
:> a bit ant it looks like they get dropped in OVS land.
:>
:> The VM's main function in life is to pull down webpages from other
:> sites and analyze as requested.  During peak times ( EU/US working
:> hours ) it sometimes hangs some requests and sometimes fails.
:>
:> Looking at traffic the out bound SYN request from VM is always good
:> and returning ACK always gets to physical interface of the hypervisosr
:> (on a provider vlan).
:>
:> When packets get dropped they do not make it to the qvoXXXXXXXX-XX on
:> the integration bridge.
:>
:> My suspicion is that OVS isn't keeping up eth1-br flow rules remaping
:> from external to internal vlan-id but neither quite sure how to prove
:> that or what to do about it.
:>
:> My initial though had been to blame contrack but drops are happening
:> before the iptables rules and while there's a lot of connections on
:> this hypervisor:
:>
:> net.netfilter.nf_conntrack_count = 351880
:>
:> There should be plent of overhead to handle:
:>
:> net.netfilter.nf_conntrack_max = 1048576
:>
:> Anyone have thought son where to go with this?
:>
:> version details:
:> Ubuntu 14.04
:> OpenStack Mitaka
:> ovs-vsctl (Open vSwitch) 2.5.0
:>
:> Thanks,
:> -Jon
:>
:> --
:>
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