Cannot change br-int and br-tun MTU to >1500
we have a server setup where openstack components are KVM-VMs:
icehouse-controller.
icehouse-network.
icehouse-cinder.
All these components are attached to a bridge br-main-vm over subinterface (vlan 112) --> em2.112 of the main giga-ethernet interface em2.
Thus, VM --> br-main-vm --> em2.112 --> em2.
- All interfaces have mtu=9000 configured in the interfaces file.
- Further each VM has its interface configures to mtu=9000.
- Pinging and passing data can be performed with packet > 1500.
However, br-int and br-tun (GRE) MTUs cannot be configured. They have by default 1500. I tried the veth_mtu = 9000 in the [agent] section of ml2_conf.ini but in vain.
I do not want to reduce the guest VM MTU; thus, how to proceed.
Hint: I tried to change the MTU in: nano /sys/devices/virtual/net/br-tun/mtu and nano /sys/class/net/br-tun/mtu but it did not work, ovs rewrite them.
Regards Marwan
Did you try changing this with ifconfig? It might be as "simple" as writing a script that runs after startup to ifconfig mtu=blah. I don't see this option set in ovs natively. I know that there are ways to do this because people are able to configure it.
Hi, I am also facing similar issue, were you able to find out the solution ?