[libvirt-users] How can a bridge be optimized?

Henrik Ahlgren pablo at seestieto.com
Tue Jun 12 15:14:00 UTC 2012


On Tue, Jun 12, 2012 at 10:24:24AM -0400, Whit Blauvelt wrote:
> The host is Ubuntu 10.10 with the 2.6.35-28-server kernel. Libvirt is
> 0.8.3-1ubuntu19.4, qemu-kvm is 0.12.5+noroms-0ubuntu7.11. Not sure how that
> relates to "Get kvm version >= 60" (from http://www.linux-kvm.org/page/Virtio)
> but it's at least a "Kernel >= 2.6.25". 

The relationship between KVM and QEMU is all too confusing, but
nowadays you should only need to care about the qemu-kvm version (?). 0.12
is quite old and Ubuntu 10.10/maverick no longer receives (security)
updates, so you should consider upgrading if posssible. If upgrading
the whole distro is infeasible, you might be able to install qemu-kvm
and libvirt from a newer Ubuntu release without bringing in too much
dependencies.

>     <interface type='bridge'>
>       <mac address='00:16:36:89:65:2e'/>
>       <source bridge='br0'/>            
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
>       <model type='virtio'/>                                                     
>     </interface>            

I like to use network type interfaces and "logical" network names, but
this should work fine.

You might want to experiment with different offload settings (ethtool
-k) to see if they make any difference with the igb card. Also, have
you tried measuring the performance between the host and a guest?




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