Hi Darragh, Yes, Instances are getting MTU 1400.
I'm using LibvirtHybridOVSBridgeDriver at my Compute Nodes. I'll check BG 1223267 right now! The LibvirtOpenVswitchDriver doesn't work, look: http://paste.openstack.org/show/49709/ http://paste.openstack.org/show/49710/ My NICs are "RTL8111/8168/8411 PCI Express Gigabit Ethernet", Hypervisors motherboard are MSI-890FXA-GD70. The command "ethtool -K eth1 gro off" did not had any effect on the communication between instances on different hypervisors, still poor, around 248Mbit/sec, when its physical path reach 1Gbit/s (where GRE is built). My Linux version is "Linux hypervisor-1 3.8.0-32-generic #47~precise1-Ubuntu", same kernel on Network Node" and others nodes too (Ubuntu 12.04.3 installed from scratch for this Havana deployment). The only difference I can see right now, between my two hypervisors, is that my second is just a spare machine, with a slow CPU but, I don't think it will have a negative impact at the network throughput, since I have only 1 Instance running into it (plus a qemu-nbd process eating 90% of its CPU). I'll replace this CPU tomorrow, to redo this tests again but, I don't think that this is the source of my problem. The MOBOs of two hypervisors are identical, 1 3Com (manageable) switch connecting the two. Thanks! Thiago On 25 October 2013 07:15, Darragh O'Reilly <dara2002-openst...@yahoo.com>wrote: > Hi Thiago, > > you have configured DHCP to push out a MTU of 1400. Can you confirm that > the 1400 MTU is actually getting out to the instances by running 'ip link' > on them? > > There is an open problem where the veth used to connect the OVS and Linux > bridges causes a performance drop on some kernels - > https://bugs.launchpad.net/nova-project/+bug/1223267 . If you are using > the LibvirtHybridOVSBridgeDriver VIF driver, can you try changing to > LibvirtOpenVswitchDriver and repeat the iperf test between instances on > different compute-nodes. > > What NICs (maker+model) are you using? You could try disabling any > off-load functionality - 'ethtool -k <iface-used-for-gre>'. > > What kernal are you using: 'uname -a'? > > Re, Darragh. > > > Hi Daniel, > > > > > I followed that page, my Instances MTU is lowered by DHCP Agent but, same > > result: poor network performance (internal between Instances and when > > trying to reach the Internet). > > > > No matter if I use > "dnsmasq_config_file=/etc/neutron/dnsmasq-neutron.conf + > > "dhcp-option-force=26,1400"" for my Neutron DHCP agent, or not (i.e. MTU > = > > 1500), the result is almost the same. > > > > I'll try VXLAN (or just VLANs) this weekend to see if I can get better > > results... > > > > Thanks! > > 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 >
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