Re: Virtualization preferences

["Christoph Doerbeck" <user=1028@nabble.blu.org>]

 The requirement for VTx is only if you plan to use full virt (which has 
always been the case).  I do not believe there is such a case for para 
virt.  The only 'requirement' is for PAE, which you won't find (for 
example) on older pentium mobility processors.  Please correct me if I 
am wrong on this. 

Regarding upgrading the host and winding up with broken guests... I know 
that on Fedora 5 (I think) there was a time when upgrading the host OS's 
(Dom0) xen kernel could have left you in a bind because it introduced a 
dependency for PAE support in the guest OS's (DomU). Thus if you didn't 
upgrade the guests first, you where hosed. 

Otherwise, I've been pretty successful as far as I can recall with 
running PV guests and hosts with dissimilar versions (within reason). 
But I'd expect that if you want to make use of live migration, suspend, 
resume, etc... I'd probably advise thoughtful planning and upgrade 
schedules to keep things closer in sync. 

Last, I don't know if everything Red Hat has done filters down to 
CentOS ... [but assuming it does] ...  Part of what Red Hat did when 
integrating Xen into Enterprise Linux, was to insulate the user from the 
hypervisor implementation.  Meaning, the tooling for managing virtual 
machines is built on project libVirt ... and essentially ... down the 
road if Xen is not the "in" technology, then it can be replaced by (or 
augmented with) kvm, or what ever ... and your tools, scripts, knowledge 
stays the same. 

-cd 


On Fri, 2008-07-25 at 07:36 -0400, Jerry Feldman wrote: 
> On Thu, 24 Jul 2008 11:17:44 -0400 
> Kent Borg <[hidden email]> wrote: 
> 
> > Jerry Feldman wrote: 
> > > My preferred choices are Xen and Virtualbox. 
> > 
> > I am liking Virtualbox these days.  I used to be a fan of Xen, I was 
> > using it for running Linux guests on a Linux host, but then I was burned 
> > once by their tight coupling between guest and host versions.  I 
> > upgraded the host kernel (I think it was) and my guests were all 
> > broken.  Maybe my gripe is with paravirtualization more than it is with Xen. 
> > 
> > I have not tried Xen on a CPU with virtual extensions, though I notice 
> > the Xen Wikipedia page says "As of Xen 3.0.2, the list of supported 
> > unmodified guests is limited to certain versions of Windows (incl. XP) 
> > and Linux.".  So I fear the "para" negatives are not entirely gone. 
> 
> Thanks. I also know that Xen now requires Intel VT or AMD V series 
> CPUs. 
> 
> -- 
> -- 
> Jerry Feldman <[hidden email]> 
> Boston Linux and Unix 
> PGP key id: 537C5846 
> PGP Key fingerprint: 3D1B 8377 A3C0 A5F2 ECBB  CA3B 4607 4319 537C 5846 
> 
> --Sig_/5tlX5bSihH/YzjaNvb53Gt0-- 
> 
> _______________________________________________ 
> Discuss mailing list 
> [hidden email] 
> http://lists.blu.org/mailman/listinfo/discuss