RE: [Xen-users] Uname shows 64bits rather than 32 : yum problem. 32 bits on dom0 64 bits is it possible ?

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Pascal
> Sent: 18 June 2007 12:57
> To: Goswin von Brederlow; xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-users] Uname shows 64bits rather than 32 : 
> yum problem. 32 bits on dom0 64 bits is it possible ?
> 
> Thanks!
> 
> well....
> 
> some tell that with xen 3.0.3 it is impossible to install 32 
> bits guests on 64 bits dom0 !

It depends on the type of guest. If you have a para-virtual kernel, then the 
kernel and the hypervisor must match exactly (and since Dom0 is a kernel on top 
of the hypervisor, it must be 64-bit when the hypervisor is 64-bit). 

HVM (fully-virtual) guests can be "anything smaller than or equal to the 
hypervisor", so on a 64-bit hypervisor, you can run any type of kernel up to 
64-bit. 

> They said that it is possible only with xen 3.1 !
Correct in as much as 3.1 adds the ability to run a 32-bit PAE para-virtual 
kernel on Xen 64-bit hypervisor (and that includes that you could have Dom0 
32-bit if you want, and I think you can even use 32-bit Dom0 and 64-bit DomU if 
you should want that). 

> 
> Others tell it is !

Well, others may be wrong, depending on which of the above definitions they 
mean are able to run on 3.0.3 - I'm a Xen Developer, and I've seen the patches 
for the "32-on-64" go into 3.1. There's quite a lot of work added to support 
this, and it would have been noticable if it went into 3.0.3 instead of 3.1. 

As to using "linux32 yum" to install a para-virtual guest, it probably will end 
up with something that doesn't run (unless you also have Xen 3.1 at least).

--
Mats
> 
> Pascal
> 
> Goswin von Brederlow a écrit : 
> 
>       "Petersson, Mats" <Mats.Petersson@xxxxxxx> 
> <mailto:Mats.Petersson@xxxxxxx>  writes:
>       
>         
> 
>                
>               
>                   
> 
>                       -----Original Message-----
>                       From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
>                       
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Pascal
>                       Sent: 17 June 2007 17:43
>                       To: xen-users@xxxxxxxxxxxxxxxxxxx
>                       Subject: [Xen-users] Uname shows 64bits 
> rather than 32 : yum 
>                       problem. 32 bits on dom0 64 bits is it 
> possible ?
>                       ...
>                       I ask this becasue I have installed a 
> 32bits guets but when I 
>                       do a uname -a on the guest i have this :
>                       Linux fqdn.domain.com 
> 2.6.18-8.1.6.el5xen #1 SMP Thu Jun 14 
>                       18:01:24 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux
>                       
>                       it looks like it shows exactly the same 
> info than the dom0
>                             
> 
>       
>       It shows what it is supposed to show: The kernel you 
> are running.
>        
>         
> 
>                       It is a problem because yum, on the 
> guest, looks for 64bits 
>                       packages rather than 386 ones
>                             
> 
>       
>       That would be a pretty stupid bug in yum then. I see 
> nothing wrong
>       with running a 64bit kernel with 32bit userspace (as 
> you do). That is
>       perfectly supported in Debian.
>        
>         
> 
>                       Si it normal ?
>                       How to tell to yum to look for i386 ?
>                             
> 
>       
>       If yum really is so stupid that is uses uname then run "linux32
>       yum".
>       
>       MfG
>               Goswin
>       
>         
> 
> 



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