Re: [libvirt-users] How can I set the advertised value of MTU for virbr0 interface?

On 10/22/2015 10:57 AM, Michal Privoznik wrote: As you've found, that was reverted before it was ever in a release. After initially approving it, I realized that the free-form format of the option values was doomed to create problems in the future, and that we had to come up with a more robust syntax (essentially libvirt needed to know the datatype of each option value, rather than just accepting an opaque string and passing it on to the dhcp server). It really surprised me a month or two ago when someone asked about this on IRC and I found that we didn't support setting the MTU in a libvirt virtual network. Due to MTU being supported in host interface config, I had just always assumed in the back of my mind that it was there for networks as well, but never needed it and so never paid close attention. But when it was pointed out it was missing, my first suspicion was that there must be some reason it wasn't done (since it's so simple). And then (as usual) I went back to whatever I was working on and forgot about it :-/ It makes sense to me that the <bridge> element should have an attribute called "mtu" (this is a case where I think we shouldn't try to use exactly the same config as host interfaces, since they have a separate <mtu size='blah'/> element so that it can be used with any type of interface). So it would look something like this: <bridge name='virbr0' mtu='9000' stp='on' delay='0'/> If someone feels like implementing this that would be great. If not, it's on my list and may get implemented "someday".