[CentOS] Virtualization option at first install CentOS-5.4 x86_64

David McGuffey davidmcguffey at verizon.net
Tue Nov 17 03:08:40 UTC 2009

On Mon, 2009-11-09 at 10:18 +0100, Mathieu Baudier wrote:
> > I selected one virtual CPU for the XP load...primarily because I want to
> > run a couple more VMs and the guidance was to allocate one real CPU per
> > VM.
> My understanding is that Win XP will perform a fundamentally different
> install depending on whether it detects 1 or many CPU. So if you ever
> plan to reuse your VM with many CPUs, you should install it with many
> right away (and follow the tip above: install as Windows Vista, not
> XP).
> I had this problem with a Win XP VM that I installed with pre v3.0
> versions of VirtualBox: after VBox introduced SMP I could not use the
> multi-processor feature since XP had been installed with one
> processor.
> Anyhow, now that I'm using KVM, for my test desktop VMs I tend to
> allocate a total of CPUs across the VMs higher than the number of my
> physical CPUs, since they rarely need CPU power at the same time but I
> want them to be able to run very smoothly if needed.
> > run a couple more VMs and the guidance was to allocate one real CPU per
> Which guidance are you talking about?

In the Red Hat 5 Virtualization documentation it seems to strongly
recommends having at least one physical cpu per VM.  Since I have a quad
core and I want to run the host plus 2-3 VMs, I decided give each VM one
virtual cpu. Maybe I was too cautious.


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