Open Stack

Hi list,


I'm working under CentOS 6.4 + Havana.

I'm trying to enable jumbo frames for Openstack instances.

I'm using libvirt_vif_driver=nova.virt.libvirt.vif.LibvirtHybridOVSBridgeDriver in nova.conf.

I noticed there is a parameter in plugins/openvswitch/ovs_neutron_plugin.ini I can use, so I set it to:
        veth_mtu = 9000

And, it works fine :
       ip link |grep 9000
       6: eth4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc mq state UP qlen 1000
       263: phy-br-eth4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast state UP qlen 1000
       264: int-br-eth4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast state UP qlen 1000
       10: br-eth4: <BROADCAST,UP,LOWER_UP> mtu 9000 qdisc noqueue state UNKNOWN

But, after the instance booted, all ports used for the instance are still MTU=1500:
ip link |grep df6a018a-0d
       273: qbrdf6a018a-0d: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
       274: qvodf6a018a-0d: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
       275: qvbdf6a018a-0d: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
       276: tapdf6a018a-0d: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500

So I have to
        1. find the exact ports using by the instance
        2. change their MTU one by one
        3. enter the instance to change the MTU by hand

Is there a way that can make sure after the instance booted, all ports have MTU=9000 without change by hand ??

Thanks.
-chen

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