On Mon, Feb 14, 2011 at 2:34 PM, Smithies, Russell <Russell.Smithies at agresearch.co.nz> wrote: > I’ve got xen-3.0.3-105.el5_5.5 running on Centos 5.5 and all is running > smooth but I notice that any VMs running under it only have access to > Realtek RTL8139C at 100 Mbps nics. In general, don't bother. Let the virtualization server handle all the cute features of the network interfaces, because it's going to *anyway* as part of its role translating the kernel operations of the virtualized driver into real hardware interactions with the NIC you actually use. > We have 4 x 1G nics configured in a port channel so I’d really like to be > able to give my VMs 1000Mbps nics. Actually test the performance, and if possible, use a para-virtualized kernel. You should see surprisingly good performance. > Does anyone know if this is possible and how to do it? > > If not, does KVM support faster nics because at this point it would be > fairly simple to change. See above. In reality, I'll be surprised if you don't easily outperform a physical RealTek device.