[libvirt-users] RX dropped packets on guests subnets

[pichon]

Hello,

I’m using the Fedora 23 disturb, with recent kernel on all of my systems ( VMs and Physicals), I see the rx packet dropped only on VMs when I disable the virtio-net driver , by adding driver name=‘emu’ in the XML.

But indeed if I started the tcpdump, the dropped stopped.

Patrick

> On 26 Jan 2016, at 20:51, Troels Arvin <troels at arvin.dk> wrote:
> 
> pichon wrote:
> 
> Hello,
> 
> pichon wrote:
>> On each of my guests VM, I see constantly a RX dropped number increasing
>> , Even if the VM does nothing !
> 
> I'm seeing the same phenomenon on one of our LANs (on another LAN, I 
> don't see it). My setup is with RHEL 7, and it is seen on both physical 
> and virtual servers. I don't see it on any RHEL 5 or 6 servers.
> 
> A strange observation: If I start tcpdump, the package drops stop. 
> (Setting the NIC in promisc mode does not have any impact; it has to be 
> tcpdump.)
> 
> I suspect that it has to do with this:
> https://www.netiq.com/support/kb/doc.php?id=7007165
> If this is the case, it's simply because recent kernels classify packets, 
> and then there's nothing to worry about.
> 
> - But Red Hat Support does not share that view. I have an open case with 
> Red Hat Support about it; lots of stuff has been tried, but we have yet 
> to reach a conclusion.
> 
> -- 
> Troels
> 
> 
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