[libvirt] 802.1q vlan-tagging support for libvirt

David Edmondson dme at sun.com
Mon Apr 27 08:33:09 UTC 2009


On Wed, Apr 08, 2009 at 12:09:06PM +0100, Daniel P. Berrange wrote:
> On Wed, Apr 08, 2009 at 01:06:48PM +0200, Maximilian Wilhelm wrote:
> > Anno domini 2009 Daniel P. Berrange scripsit:
> > 
> > [...]
> > > In the (nearish) future NICs will start appearing with SR-IOV capabilities.
> > > This gives you one physical PCI device, whcih exposes multiple functions.
> > > So a single physical NIC appears as 8 NICs to the OS. You can thus directly
> > > assign each of these virtual NICs to a different VM directly,a voiding the
> > > need to bridge them.
> > 
> > > I don't think its worth spending too much time trying to come up with other
> > > non-bridged NIC sharing setups when hardware is about todo it all for us :-)
> > 
> > Is this hope or do you know about any timelime for this?
> 
> Hardware exists today & patches are avialable for upstream Linux.
> 
> http://lwn.net/Articles/308238/
> 
> The question mark is more over how long it takes before the hardware is
> widely available & shipped to consumers by vendors.

The hardware is not appropriate for all environments. For example,
using the hardware removes the ability of the host to manage the
packet flow to the guest (filtering, bandwidth limits, etc.).

Domain migration is also complicated, though not impossible.

SR-IOV isn't the answer to all problems.




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