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

[Pasi Kärkkäinen]

On Fri, Jun 11, 2010 at 12:23:04PM +1000, Russell Coker wrote:
> 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.
> 

I guess you need the dummy=dummy hack as described in here:
http://wiki.xensource.com/xenwiki/XenCommonProblems

-- Pasi