Which VirtualMachine to use ??

Let me just illustrate my findings after searching for a good VM to be used.

Our requirements :
1) Supported by libvirt.
2) Open Source and Free (as in freedom)
3) Has a good community with active developers.
4) Fast.

How did I evaluate ?
1) Read blogs
2) Google searches (eg . which is better VBox or KVM? ,etc)
3) Look for references.
4) Benchmarks on performances ( again subject to other people’s findings and reporting)

1) Some of the websites were biased about their solution
2) I got caught between community wars( one saying VM ‘X’ is the best , another VM ‘Y’ is the best, both were convincing enough)
3) Libvirt lack of good documentation about the different features available for different VMs.

A comparision table:

Criteria Xen Qemu+KQemu KVM VirtualBox
Host OS Linux,Solaris,BSD Most Linux
Guest OS Most(Kernel needto
be modified)
Most Most Most
Speed Performance loss on
diskintensive operations
Qemu is usually slow.But Kqemu has

good performance

Goodperformance Goodperformance
Virtual Hard
DiskImage Format




Community Support Community not very
active in the

past few years

Support droppedfor KQemu RedHat is currentlysupporting it Oracle is currentlysupporting  it

Now considering this table I had a rough idea of shortlisting the list to two candidates : KVM and VirtualBox.

Reasons for choosing Vbox over KVM
1)Vbox support for multiple platforms
2)KVM’s native disk image QCOW2 is very slow. Ofcourse I could use other disk images but that would require external tools.
3)KVM’s dependency on linux kernel

And the winner is VirtualBox


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