[one-users] Can I use more hosts for just one VM?

[Jelle Herold]

On Fri, Jun 11, 2010 at 01:38:38PM +0200, Daniele Fetoni wrote:
>
> Maybe my question is stupid, but I found nothing in documentation, so
> I want you to ask: is possible with opennebula create a VM using
> resources from several hosts?
>
> I mean, if I have two cluster nodes with 2 cores each one, can I
> deploy a VM requiring 3 cores?

No you can't, the underlying hypervisors (KVM,Xen) cannot span multiple
machines.

This not suprising: cores need to talk to each other because they
usually share state (memory, locks, etc). So, for this reason the
communication channel between cores can become a bottleneck.  Bandwidth
between two chips in a modern machine is extremely high: around 100
Gbit/s or more! (Contrast this with a 1Gbit/s network).

Then there is latency and lots of other complicated issues, but you
are entering grid-computing terrain here :-)


Regards,
Jelle.
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