I currently have the following environments on my laptop:
. Windows Vista¹
. Debian ‘lenny’
. Debian ’squeeze’
. Ubuntu 10.10
Considering that the way they are set up, I never use more than 10-15%
of the 4G of RAM that came with this laptop. I thought it might be worth
trying to install a Xen dom0 on a separate partition and migrate the
above environments to four virtual machines.
The first problem I have run into is that I have not been able to boot
the debian-based dom0 that I installed on a separate partition into
anything other than the basic VGA console, with a blurry font and
letters as big as houses, something that makes it very difficult to
investigate a problem when for any reason X is not available.
As soon as I switch from the default squeeze default kernel install to
the squeeze Xen AMD64 kernel, boot command tweaks such as ‘vga=893’ or
‘video=uvesafb:1920x1200’ are ignored, making me think that this
particular kernel cannot switch to a framebuffer console.
Is this a limitation of Xen kernels, or is it specific to the Xen AMD64
kernel that ships with debian squeeze?
The second problem is that when I start X on the dom0, the desktop comes
up with a 1600x1200 resolution, which is incorrect in terms of aspect
ratio (4:3 rather than 16:9) and of course the fonts in GUI applications
and terminals alike are blurred and barely legible.
I noticed in the Xorg log that rather than the nividia ‘nouveau’ driver,
which is the default with debian squeeze, the X server falls back to the
VESA driver when I boot the Xen kernel, and that the xrandr command
indeed lists 1600x1200 as the highest resolution.
On the other hand, ‘hwinfo --vbe | grep Mode’ correctly lists the
Here again, and despite about a week of googling for answers, I have not
been able to determine whether I am running into Xen kernel limitations
or if this is due to the configuration of the Xen squeeze AMD64 kernel.
If I had, I would have downloaded a source Xen kernel and compiled it
A third problem that I have not even been able to actively research
since I am stuck with the dom0 problems described above and have yet to
set up my virtual machines, is that when I use the Xen 2.0 LiveCD, I am
seeing horrendous performance on the desktop-type demo machines.
Naturally part of the problem would be due to my running the Xen
environment off of a LiveCD, but that should not affect such matters as
moving the pointer around the screen..??
I still have fond memories of Vmware Workstation 3.0, that I used long
ago on a laptop whose hardware was something like an order of magnitude
less powerful than my current machine: I was able to run my linux host
on VT7, and two guests on VT8 and VT9, and provided I didn't start any
CPU-intensive tasks on any of the VM's, all three worked quite nicely,
almost as if they were the sole environment running on top of my
Naturally, I do not claim having thoroughly investigated these aspects
but before I invest yet more time, I thought I should make sure that
what I am trying to achieve is at all possible in the first place.
After all, since these are desktop environments, and though they do use
quite a bit of RAM, only one of them will be active at any point in
time: I only have two hands and one pair of eyes. In terms of
performance, I thought that the overhead caused by my idle desktops
whould be negligible.
Is Xen the right tool for desktop virtualization or should I look
¹ Only kept while the laptop is under warranty, in the event I need some
common ground to work with the manufacturer's tech support.
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