Sun's FOSS VirtualBox hits the sweet spot for Linux (ITWire)

In a way, it goes beyond that. Virtualbox is partially based on QEMU, although the wikipedia
article for qemu suggests they have improved on QEMU through more static code analysis.

Does Xen+VT still have to bounce IO around between hardware, domain0 and guest?

The thing about Virtualbox is that it's user friendly. It has a nice user interface and is
generally pretty easy to do.

For example the non-free one supports USB 2.0. You can use the GUI to add and remove USB
devices on the fly. It supports automatically resizing the Windows desktop so that you can
resize the VM display like any other desktop application. 

For the fully-free crowd KVM is probably the closest, but it completely lacks any sort of easy
user interface. It's one of the things that they really need to work on.

Xen, in comparison, isn't even on the map. It's much to much of a PITA to lift your OS into a
hypervisor to get Xen working. It's totally unsuitable for the sort of work that Virtualbox is
good at.

Now for server work, that's different. 

Now I like KVM and I think that it can do it all. Were you don't have hardware to support KVM
then Kqemu is pretty darn close-enough. But I can't comfortably tell my friends to ever use
that software since I know they won't be able to get the sort of stuff they need working
working.

the only way to run an unmodified OS without chip support is with emulation. Qemu, virtualbox,
and vmware all support this mode of operation.

if you can take advantage of the support in recent chips for virtualization, you can do less
emulation and gain a significant speed advantage.

but to claim that virtualbox doesn't so emulation, doesn't require chip support, and can run
unmodified OSs is incorrect.

On CentOS we have also seen comparable idle guest load. Setting the timer frequency
(CONFIG_HZ) to a lower value will often help much. Of course, it's up to you to decide if
that's ok for your workload.

There's more information here:
http://bugs.centos.org/view.php?id=2189

If you are doing a lot of Linux on Linux virtualization, check out the two OS Virtualization
systems available for Linux: 1) OpenVZ and 2) Linux-VServer.  Both are good but my personal
preference is OpenVZ.

Xen and KVM work well... but... OS Virtualization is much lighter and more efficient than
machine / hardware virtualization and provides much greater density and scalability.  The
large number of dynamic resource management parameters offered by OS Virtualization are a big
bonus too.

I find it a bit snappier than vmware as well, and dead easy to use. Very stable with an
extremely attractive feature set. On my debain machine it uses 0-2% idle CPU, but not
noticable on my machine's performance at all. I think it's a beautiful product, and just hope
Sun won't screw it up, since the repositories disappeared, and it became a download and
install only product. It would be great to have it 100% FOSS as well. If they can stay on the
straight and narrow, virtualbox should have a shining future.

> Second (this not VirtualBox's fault
> obviously) Fedora doesn't have a VirtualBox package

Well in a way it is.  They like to issue press releases that they are a GPL product.  Fedora
is smart enough to read the actual license terms and realize it ain't even close.  The Free
Software edition is basically the QEMU bits that were themselves GPL and the bits of
VirtualBox that are so entangled with QEMU that they really have no other choice than release
them as GPL.  All of the user friendly bits and neat features (USB) are only available in the
closed binary blob.

You can't even redistribute a package built from the GPL sources without either receiving
their permission (which can't be passed down) or changing the name from virtualbox.  Although
Fedora manages to live with compromising their principles with Firefox, VirtualBox isn't
important enough to do a trademark deal and flamewar over.

So it will probably be outside of Fedora forever... but will probably show up in freshrpms or
another 3rd party repo eventually.