On Thu, 17 Jan 2008, Troy Dawson wrote: > John Summerfield wrote: >> Jan Iven wrote: >>> On 17/01/08 02:45, John Summerfield wrote: >>>> Jan Iven wrote: >>> .. >>>>> SL4 can then run as a domU, with some caveats (cannot mix 32/64 bit >>>>> doms). >>>> I'm not sure about that. I run 64-bit Fedora 8 on Intel, and run >>>> several 32-bit guests. >>> Sorry - I was unclear and perhaps wrong. As stated on >>> http://www.linuxtopia.org/online_books/centos5/centos_5_xen_virtualization/centos5_ch-virt-hw-support.html >>> >>> >>>> With Red Hat Virtualization, 32-bit hosts runs only 32-bit >>>> paravirtual guests. 64-bit hosts runs only 64-bit paravirtual guests. >>>> And a 64-bit full virtualization host runs 32-bit, 32-bit PAE, or >>>> 64-bit guests. A 32-bit full virtualization host runs both PAE and >>>> non-PAE full virtualization guests. >>> This could have changed with 5.1 - Red Hat claims on >>> http://www.europe.redhat.com/rhel/virtualization/ that 5.1 now has >>> >>>> # The ability to run 32-bit para-virtualized guests on x86-64 systems >>>> running in 64-bit mode. >>> (I guess they are talking about the dom0 here) >> >> Well, I did mention my experience is on F8:-) I've only one system with >> hardware virtualisation, and its first level OS is Fedora 8. >> >> I use it to answer questions such as "Can I take this windows system run >> it on different hardware without it barfing because it's become >> unactivated?" and to similarly play with Windows domains. >> >> I seem to have an inordinate array of problems:-( Fortunately, Fedora >> has two virtualisation technologies, there's also KVM, and sometimes one >> works when the other does not. >> > > Just so you know, because this was discussed on Fermi's mailling list. > > The xen in SL 5.1 is 3.0.3, the same as RedHat's. > > RedHat's original release announcement said that you can run 32 bit > paravirtualized guests on 64 bit xen hosts. > RedHat's engineers then quickly said "No it doesn't, don't do it. We need to > change the announcement." The Release Notes for 5.1 state that this is a "Technology Preview" and thus is not supported. The announcement that is mentioned above is on RedHat's web area . -Connie Sieh > > Last time I checked, RedHat hadn't changed the announcement, so we ran some > testshere at Fermi. > > On SL5 is technically possible to get a 32 bit guest paravirtulized guest > running on a 64 bit host. But don't do it. It will crash. The longest we > ever got one to stay up was 5 minutes. Most won't even fully boot before > crashing. > > We had some users that needed 32 bit guests on 64 bit hosts, so they updated to > the latest stable xen (3.1.x I believe) and they were able to do it, and it > seemed to be stable. > > Fedora 8 (and possibly 7) has the latest xen in it, so it most likely that they > have the version that will do 32 bit guests on 64 bit hosts. > > Troy >