Hi Thiago, you don't say what version of OVS. It must be >=1.10.0 because you are using VXLAN. From that version the way MTU and tunnels is handled has changed.
See "- Tunneling: " in http://openvswitch.org/releases/NEWS-1.10.0 Here is a tcpdump with with OVS 1.10.2 where all interfaces have an MTU of 1500. GRE tunnels are used and there are no connectivity problems. http://paste.openstack.org/show/50025/ The messages with "IP truncated-ip - 18 bytes missing!" mean IP fragmentation is happening. Re, Darragh. > Guys, > > I am not detecting any problems related to "MTU = 1500" when using VXLAN! > > It is easy to reproduce the "GRE MTU problem", when using GRE tunnels with > MTU = 1500, from a Instance, it is impossible to use RubyGems (Ubuntu 12.04 > Instance), for example, "gem install bundler" (neither "bundle install" > your RoR App) doesn't work with MTU 1500 on top of a GRE tunnel, with MTU > 1400 is fine. > > But, now with VXLAN, I'm using MTU 1500 again without any problems! > > Honestly, I don't know for sure if RubyGems changed too or, if it is > related to VXLAN being a bit better than GRE, anyway, I'll keep my Havana > cloud running with MTU 1500 from now on. > > Cheers! > Thiago _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : openstack@lists.openstack.org Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
