Re: Xen vs KVM
On Wed, Mar 28, 2012 at 1:44 PM, Hilco Wijbenga
<hilco.wijbenga@gmail.com> wrote:
> On 28 March 2012 06:43, Aaron Toponce <aaron.toponce@gmail.com> wrote:
>> On Wed, Mar 28, 2012 at 09:35:25AM +0100, Jon Dowland wrote:
>>> For me, it became yesterday's technology when it became apparent that
>>> the hypervisor model (putting an entirely new kernel between Linux and
>>> the hardware) created all sorts of performance problems, and neglected
>>> the decades of work that had gone into the Linux network stack, amongst
>>> other parts. Increasingly ugly hacks were (are) needed to pass through
>>> to the privileged domain, all of which is totally unnecessary with the
>>> KVM model, where the (much more) tried and tested Linux kernel goes on
>>> the bottom of the pile.
>>
>> Can you expound on these "ugly hacks"? The Xen kernel is a full type-I
>> hypervisor, with unfettered access to the hardware. The dom0 presents the
>> virtualized hardware to the domU guests. Using Xen HVM, the presentation
>> uses Qemu, which is exactly the same for KVM.
>
> You might both be interested in the PDF linked to at the bottom of
> [1]. It explains why Qubes OS went with Xen and not KVM. I thought it
> was quite interesting (I used to be firmly in the KVM camp, now I'm
> not sure any more. :-) ) Mind you, their focus is mainly security.
>
> [1] http://www.qubes-os.org/Architecture.html
>
Xen requires a patched kernel. It is unstable. It crashed on
me randomly before I got as far as configuring any VM stuff.
The system which experienced this returned to a standard
Debian kernel and never had a problem again.
KVM is native part of kernel. It is stable. I've been running on several
systems for over a year and no crash.
Both share the same qemu devices and drivers land.
You can read what IBM has to say about key benefits and security
features of kvm...
ftp://ftp.software.ibm.com/linux/pdfs/LXW03004-USEN-00.pdf
A big clue is Redhat is dropping xen virtualization going forward.
Kvm will get more development support than xen.
I see no reason to even consider xen.
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