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Re: Xen, Squeeze, and Beyond

"Andrew M.A. Cater" <amacater@galactic.demon.co.uk> writes:

> On Thu, Feb 25, 2010 at 04:53:56PM -0600, John Goerzen wrote:
>> Hi folks,
>> There was a thread here a little while back about the status of Xen in
>> future Debian releases.  It left me rather confused, and I'm hoping to
>> find some answers (which I will then happily document in the wiki).
>> According to http://wiki.debian.org/SystemVirtualization :
>> "Qemu and KVM - Mostly used on Desktops/Laptops"
> Yes - but also the only game in town for cross platform emulation.
> KVM is shaping up well and appears to be very well supported by Red Hat.

But still slower and less secure due to qemu.

>> "VirtualBox - Mostly used on Desktops/Laptops"
> Who knows what will happen to this now that Oracle own it? It's possible 
> it will be merged in one of their other products like Virtual Iron.
>> "Xen - Provides para-virtualization and full-virtualization. Mostly used
>> on servers. Will be abandoned after squeeze."
> I think that the problem here is that Xen isn't mainstream in the 
> kernel. It takes a long time for a Xen-ified kernel to come out and any 
> distribution supporting it has to carry a heavy patch burden. Xen 
> doesn't keep anywhere current in terms of kernel - if we release Squeeze 
> this year with kernel 2.6.3*, Debian will have to maintain all the patches
> / "forward port" them to 2.6.32 or 2.6.33 as was done with 2.6.2*. 

I think we can all agree that the old style xen patches from 2.6.18 and
forward ported to newer kernels in lenny are unmaintainable.

But the pv-ops xen kernel is shaping up well and that is what Bastian
Banks is working on. They have a proper upstream and follow the latest
vanilla kernel well enough. According to the wiki the plan is to have
pv-ops merge into vanilla with 2.6.34.

>> The Xen page on the wiki makes no mention of this.
>> So, I am wondering about our direction in this way:
>> 1) Will a squeeze system be able to run the Xen hypervisor?  A Xen dom0?
>> 2) Will a squeeze system be able to be installed as a Xen domU with a
>> lenny dom0?  What about squeeze+1?
>> 3) What will be our preferred Linux server virtualization option after
>> squeeze?  Are we confident enough in the stability and performance of
>> KVM to call it such?  (Last I checked, its paravirt support was of
>> rather iffy stability and performance, but I could be off.)
>> 3a) What about Linux virtualization on servers that lack hardware
>> virtualization support, which Xen supports but KVM doesn't?
> Which servers that lack hardware virtualisation support - 
> pretty much everything made in the last two or three years has it. For servers,
> specifically, the likelihood is that - Lenny has a 2 year life + 1 year, 
> Squeeze has ? year life + 1 year - by the time you get to Squeeze + 1 
> anything that doesn't will be almost ten years old. QEMU will work. 
> Non-Intel - ARM, PPC ... may be another matter.

Just end of last year I bought myself a nice POV/ION330 board (Atom 330
cpu) with 4GB ram. Makes no noise, eats little power and can decode
movies in hardware. The ideal desktop for a non-gamer. But no kvm

There are still a lot of cpus being made that don't have hvm. And
systems are being used longer than 10 years too. My Amiga is coming up
on 20 years. :) Hey, even last years I saw someone asking about actual
i386 support.

And what about ia64? Does kvm support that?

>> 4) What will be our preferred server virtualization option for non-Linux
>> guests after squeeze?  Still KVM?
>> 5) Do we recommend that new installations of lenny or of squeeze avoid
>> Xen for ease of upgrading to squeeze+1?  If so, what should they use?
> New Squeeze - use KVM? New Lenny - whatever you want, because at this 
> point you have (days until release of Squeeze + 1 year) to find an 
> alternative.
>> 6) Are we communicating this to Debian users in some way?  What can I do
>> to help with this point?
>> Thanks,
>> -- John
> Just my 0.02c
> AndyC


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