Re: Migrate/Save of 32-bit domU Broken on Xen 3.1.2 64-bit dom0

[Joshua West <jwest@brandeis.edu>]

Dang, doesn't work in Xen 3.1.3-rc1 (like you said/expected), with or 
without Kurt's patches.

Hmm... I thought 32-bit paravirtualized domU's on 64-bit dom0's were 
supported in Xen 3.1.x?  Or am I mistaken?

Perhaps standard features such as start/shutdown/pause of 32-bit PV 
domU's on 64-bit dom0's are supported, but not the more advanced 
management features like save and migrate - and I was just unclear from 
the beginning?

And of course... the final question that all developers hate... when 
s/could one _hope_ (not expect!) to see save/migrate functionality of 
32-bit PV domU's on 64-bit dom0's? :-D

Our whole reason for moving to 64-bit dom0's was to utilize 32GB of 
memory, instead of the 16GB limitation on 32-bit PAE dom0's.  We can't 
convert all of our virtual machines (100+) to 64-bit linux as its too 
much work and some actually have to be 32-bit due to vendor supplied 
software (Oracle, Zimbra, etc).  I suppose we'll wait to move to 64-bit 
until [live] migration is available, as its used quite frequently in our 
machine rooms.

Thanks for all of your help Keir and Kurt.

Keir Fraser wrote:
> Looking at the issues that need to be handled to support this, it cannot be
> expected to work.
>
>  -- Keir
>
> On 18/1/08 22:13, "Joshua West" <jwest@brandeis.edu> wrote:
>
>   
>> Ahh.  Well, I'm building xen-3.1.3-rc1 right now and I'll see how that goes.
>>
>> Keir, have you seen this issue before?  Where one cannot xm save/migrate
>> a 32-bit domU on a 64-bit dom0?  Or is this expected to work and just
>> doesn't go well for me?
>>
>> Keir Fraser wrote:
>>     
>>> On 18/1/08 22:05, "Joshua West" <jwest@brandeis.edu> wrote:
>>>
>>>   
>>>       
>>>> Just to make sure the patches aren't the cause of this new error
>>>> message, I'm going to see what happens with Xen 3.1.3-rc1 w/o patches.
>>>>
>>>> Kurt, Keir, everybody else... any ideas as to why "xm save" (and thus
>>>> "xm migrate") of 32-bit domU's does not work on 64-bit dom0's?  Has
>>>> anybody found this to be successful in the past?
>>>>     
>>>>         
>>> The extent of the patches that Kurt posted indicate its pretty unlikely to
>>> work without considerable code modification. I guess those patches aren't
>>> quite fully baked yet, unfortunately, or haven't been written with your
>>> precise case in mind.
>>>
>>>  -- Keir
>>>
>>>
>>>   
>>>       
>
>
>   


-- 
Joshua West
Systems Engineer
Brandeis University
http://www.brandeis.edu