[ovs-discuss] Drops in OVS

[Flavio Leitner]

On Thu, Jul 30, 2015 at 05:56:29AM +0530, Abhishek Verma wrote:
> Hi,
> 
> I have 3 switches connected via OVS like this:
> 
> R1 -- R2 -- R3
> 
> I am doing an iperf test using TCP between R1 and R3. R1, R2 and R3 are
> spread out geographically and i use a VXLAN tunnel to connect them.
> 
> iperf test shows me considerable packet losses. However, ovs-vsctl get
> interface stats is showing me zero losses on all the legs.
> 
> This means that OVS for example on R2 forwarded all the packets that it
> recieved on the VXLAN tunnel from R1 to R3. Is my assumption correct. This
> means that the packet losses reported by iperf are the packet losses in the
> network and not because of OVS.
> 
> Besides interface statistics is there any other way to get packet drops by
> OVS?

You might have drops at the NIC level, so check ethtool -S output or
bad flows  which for some reason is dropping packets too.

fbl