[Pkg-xen-devel] [RESENT] Re: Xen for Squeeze, 3.4 or 4.0

[Russell Coker]

On Fri, 11 Jun 2010, Bastian Blank <waldi at debian.org> wrote:
> On Thu, Jun 10, 2010 at 05:54:28PM +0200, Bastian Blank wrote:
> > I'm currently thinking about which version of Xen supporting in Squeeze.
> > There are two possibilities: 3.4 and 4.0. 3.4 is currently in testing
> > and unstable, 4.0 is in experimental.
> > 
> > Xen 3.4
> > =======
> > Pros
> > - Proofed to be stable

Not on my machines it hasn't.  One i386 server which ran Lenny/Xen for ages 
without problems (since before Lenny was released) is now running Xen 3.4 from 
Unstable and it's not going particularly well.  The other day it was in a 
cycle of booting and crashing when loading 2.6.32, I booted 2.6.26 and then 
before the init scripts finished I rebooted with 2.6.32 and it worked.

Different machines require different amounts of memory reserved for Dom0 for 
unknown reasons.

A couple of other machines which according to the Xen web site have suitable 
CPUs won't boot the Xen kernels that are currently in Unstable.

It just seems flakey to me.

> > Cons
> > - NUMA-mode only opt-in, no infos about stability
> > - Fails on several modern machines because of IO-APIC problems

It fails on plenty of i386 machines (P3 class) for me.

> > Xen 4.0
> > =======
> > Pros
> > - NUMA
> > - More tested with the Kernel in Squeeze
> > Cons
> > - Quite new
> > 
> > My personal preference would be to go with 4.0.

Based on my experience with Xen I think that we should have both.  Then if one 
doesn't work we can try the other.

My impression of Xen stability is that trying two different versions and 
hoping that one will work is a good strategy for any given server.

Bastian, thanks a lot for all your great work on this, it's very important to 
me and to lots of other people!

But through no fault of anyone in the Debian project I expect that an ideal 
result of one version that works well for almost everyone can't be achieved.


PS  It would be nice if we could get Grub2 updated to boot Xen kernels.  My SE 
Linux Play Machine is offline right now because I messed up the Grub2 
configuration so badly that it won't even give me a boot menu.

-- 
russell at coker.com.au
http://etbe.coker.com.au/          My Main Blog
http://doc.coker.com.au/           My Documents Blog