[Beowulf] cloudy HPC?

[Bogdan Costescu]

On Thu, Jan 30, 2014 at 9:57 PM, Mark Hahn <hahn at mcmaster.ca> wrote:
> by "HPC services", I mean a very heterogenous mixture of serial, bigdata,
> fatnode/threaded, tight-coupled-MPI, perhaps
> even GP-GPU stuff from hundreds of different groups, etc.

What would running in VMs bring as an advantage to these jobs relative
to running on bare-metal ?

> but VM infrastructure
> like KVM can give device ownership to the guest, so IB access *could* be
> bare-metal.

So you start a VM and you assign an IB card to it. What do you assign
to another VM running at the same time on the same node ? If there can
only be one job accessing the IB card bare-metal, is it worth using
VMs at all ? Of course, if you have multiple IB cards per node, you
can assign each to a VM - but this only works if they don't share the
same interrupt.

Cheers,
Bogdan