[ovs-discuss] Port satturation?

Jesse Gross jesse at nicira.com
Tue Oct 11 22:12:27 UTC 2011


2011/10/11 Vladimir Nikolić <vladimir.nikolic at amis.si>:
> Hi,
>
> we are expiriencing some very strange behaviour on our XenServer 6.0
> server (openvswitch-1.0.99-104.9871).
> On fake bridge xapi2 we have 2 VM, each with one interface:
>
> # ovs-vsctl list-ports xapi2
> vif1.0 (VM1, ip 1.1.1.1)
> vif2.0 (VM2, ip 1.1.1.2)
>
> VM1 is mail server, with traffic peaks at 15Mb/s. Mail logs are sent to
> syslog server (1.1.1.3) which is on the same vlan as VM1 and VM2.
> Problem is that VM2 is receiving some unicast traffic that is sent from
> VM1 to servers on same vlan (99.9% of that traffic is UDP):

Does the syslog server ever transmit?  I'm guessing that it does only
very rarely since it is receiving UDP unicast packets.  If it does not
transmit, then Open vSwitch will not know where to send the traffic
and will flood it to all ports.  Eventually when the server does
transmit for some reason (i.e. ARP response) the MAC will be learned
and traffic is directed to it but eventually the MAC will age out
until it transmits again.



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