Hello,

We have been tuning our libvirt hosts and discovered that setting the txqueuelen on vnetX devices to 2500 we can increase the network throughput by a factor of almost 10. On an eth device it can be set by  hand/rc.local with the following instructions http://www.cyberciti.biz/faq/gentoo-centos-rhel-debian-fedora-increasing-txqueuelen/  .  Because vnetX devices are named on a 'first free' basis and they come and go with the guests the rc.local method is not going to work. I think this needs to be done via libvirt or possibly udev, maybe with some kind of hook. Ideally I would like to be able to set this automatically for all vnetX devices when they are created or even better, on a per guest basis.



Tim Hughes
mailto:thughes@thegoldfish.org