Re: [Qemu-devel] Qemu Questions

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Nov 09, 2007 at 08:42:52PM -0500, admin@mmri.us wrote:
> I must apologize for subscribing to this list, but the Qemu users list 
> is dead, sop this is my only option.
> I understand it is a development list, but I would appreciate some help.
> 
> I will make it concise.
> 
> 1) What is the best Distro to run Qemu on with the least hassles?
> FYI, I now run it on FC7, but it is a lot of trouble. kqemu refuses to 
> work on FC7 on a v20z Sun dual cpu dual core rack server
> XEN just completely doesnt load even though  the Kernel is XEN, but at 
> least qemu works with the following Caveat;
> "Could not open '/dev/kqemu' - QEMU acceleration layer not activated"

As a general rule (with a couple of exception) Fedora only ships kernel
modules which are in upstream LKML sources. kqemu is not upstream, so it
is not included in Fedora RPMs for QEMU.

> 2)  Does an activated QEMU acceleration layer (missing above)  make a 
> huge difference?

Yes, it improves performance signficantly - although not all OS will run
under kqemu.

> 3) I have several operating systems successfully loaded in Qemu 
> sessions, but networking is just not working. I worked through loads of  
> FAQs from the net, but to no avail.

With Fedora 7 you can try  'virt-manager' which will let you setup QEMU
guests, which by default have NAT'd access to the outside world. If you
setup your host network in appropriate manner they can also be bridged
In this doc where you see 'kvm' - 'qemu' applies  just the same way

http://watzmann.net/blog/index.php/2007/04/27/networking_with_kvm_and_libvirt

The main potential gotcha I know is that ip_forward must be enabled

eg, 

$ /sbin/sysctl net.ipv4.ip_forward
net.ipv4.ip_forward = 1


> 4) Finally is there a preferred distro which is known to solve all the 
> problems mentioned above?

Networking should work correctly for NAT & bridging (assuming suitable host
config). KQEMU won't work in Fedora since the module is not upstream.

Regards,
Dan.
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