[Users] ovirt 3.2 - high multicast packet loss

Winfried de Heiden wdh at dds.nl
Mon Mar 18 14:20:39 UTC 2013


Hi all,

Playing around with Red Hat Clustering, it turns out I have a hughe 
multicast packet loss: (Centos 6.4 - x86_64  with all updates)

omping 192.168.1.211 192.168.1.212 -c500 (node1)
omping 192.168.1.212 192.168.1.211 -c500(node2)

will give almost 50% loss!

192.168.1.211 :   unicast, xmt/rcv/%loss = 500/500/0%, 
min/avg/max/std-dev = 0.330/0.610/0.789/0.064
192.168.1.211 : multicast, xmt/rcv/%loss = 500/268/46%, 
min/avg/max/std-dev = 0.416/0.635/0.921/0.066

192.168.1.212 :   unicast, xmt/rcv/%loss = 500/500/0%, 
min/avg/max/std-dev = 0.388/0.653/0.863/0.069
192.168.1.212 : multicast, xmt/rcv/%loss = 500/263/47%, 
min/avg/max/std-dev = 0.396/0.670/1.080/0.074

OK, I am using simple hardware, but this hardware is virtually doing 
nothing...

As mentioned on 
https://access.redhat.com/knowledge/sites/default/files/attachments/rhel_cluster_vm_multicast.pdf, 
I set the txqueelen to 500, same result?

I 'm still guessing whether this is an oVirt, virtio or Red Hat/Centos 
issue? Problems only happend after some time; that is 200 mo-pings shows 
everything is fine.

Anyone?

Winfried





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