[Gllug] Hardware problems / good replacements

Richard W.M. Jones rich at annexia.org
Fri Feb 10 22:05:21 UTC 2012

On Fri, Feb 10, 2012 at 07:40:21PM +0000, Phil Reynolds wrote:
> Since I upgraded my motherboard, processor and memory last summer I have
> found that virtual machines (be they under kvm or virtualbox) perform
> less well than expected.

What test are you running to determine this?

> My host system is Debian squeeze, with some backports including the
> kernel. The problem is most noticeable with kvm running FreeBSD -
> lots of WRITE_DMA timeouts on the emulated disk.

Does FreeBSD have a virtio driver?  Google is a bit unclear as to
whether a stable, finished driver exists.  In any case if you're using
IDE emulation, that would be your performance problem right there.
Use a guest that supports virtio block and network .. it'll be a lot

The second problem is Debian squeeze ... because it's old.  Using the
latest kernel, qemu-kvm and libvirt should yield significantly better

> The motherboard is an Asus M5A99X EVO, and I am using a 6 core Phenom
> processor (1090T I think). I currently have 8GB of RAM, far more than I
> am allowing VMs, and I am not, at least at present, trying to run more
> than one at a time.

A 6 core Phenom surely has enough oomph to run virtual machines fast
(although not as fast as if you're using virtio and the latest
software).  To check, you could compare your cpu flags to this page:


To check for a defective processor / cache etc. look at 'mcelog'.


Richard Jones
Red Hat
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