Hi Tangqing, This is a well-known problem, it is because GRE/VxLan 's packet header use some bytes, length of data packet should reduced. You can get refer to bellow pages: http://www.chriscowley.me.uk/blog/2014/03/31/openstack-neutron-performance-problems/ https://ask.openstack.org/en/question/25947/openstack-neutron-stability-problems-with-openvswitch/ https://openstack.redhat.com/forum/discussion/302/quantumneutron-and-ip-packet-mtus-questions-answers-and-suggestions/p1
Hope it helps, Damon 2014-10-27 9:18 GMT+08:00 Li Tianqing <jaze...@163.com>: > Hello, > Right now, we test neutron under havana release. We configured > network_device_mtu=1450 in neutron.conf, > After create vm, we found the vm interface's mtu is 1500, the ping, > ssh, is ok. But if we scp large file between vms > then scp display 'stalled'. And iperf is also can not completed. > If we configured vm's mtu to 1450, then iperf, scp all is ok. > If we iperf with -M 1300, then the iperf is ok too. > The vms path mtu discovery is set by default. I do not know why the vm > whose mtu is 1500 can not send large file. > > > Thanks. > > > > > -- > Best > Li Tianqing > > > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > >
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