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Re: [Xen-devel] Xen max supported memory per guest VM?

>>> On 14.08.10 at 23:18, Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote:
> On 14/08/2010 19:42, "Pasi Kärkkäinen" <pasik@xxxxxx> wrote:
>> Hello,
>> In http://wiki.xensource.com/xenwiki/Xen4.0 we mention the following:
>> "Better performance and scalability: 128 vcpus per guest, 1 TB of RAM per
>> host, 128 physical CPUs per host (as a default, can be compile-time increased
>> to lots more)."
>> But what's the max supported amount of memory for a (64bit) guest?
> Allocating the whole 1TB should work. It's unlikely to have been tested
> though.

Not everything will work with more than 512G: Anything that wants
to access the guest's pfn_to_mfn_frame_list_list won't work, as
there's no specification of how more than a page worth of these top
level pointers should be expressed. Affected would be (afaict) save/
restore/migrate, kexec, and dumping of a crashed guest.


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