Ashley Pittman wrote:
On Wed, 2008-01-16 at 09:18 -0500, Douglas Eadline wrote:
I get the desire for fault tolerance etc. and I like the idea
of migration. It is just that many HPC people have spent
careers getting applications/middleware as close to the bare
metal as possible. The whole VM concept seems orthogonal to
this goal. I'm curious how people are approaching this
problem.
There was a paper on this at SC, I don't know if you caught it...
http://sc07.supercomputing.org/schedule/event_detail.php?evid=11066
If I was to try and sum it up in one paragraph it would be:
"The advantages of virtulisation are obvious but for some reason the HPC
community have been slow to reap these benefits, we predict that this is
because of a perception that the performance of comms and VM operations
suffers when virtulised. This is true however we have demonstrated that
with months of work this performance loss could be minimised such that
instead of slowing down performance a lot it would only slow down
performance a bit."
I think progress is being made on the comms front, both in terms of raw
numbers (bandwidth/latency) but also in reducing CPU usage but we are
still a long way from it being widely used.
I'm constantly reminded of a meeting early on in the SCOOP project,
which I participate in (http://scoop.sura.org). "We're able to
virtualize our model applications using VMware and only see a 13%
performance hit". Note that, at this time I was tweaking for ms
upgrades in MPI communications....
We need to look at virtualization as a means of mitigating, on a
heterogeneous hardware environment, the concept of porting to every
different available machine type. In other words, I think that for a
grid environment, we might see a lot of benefit for virtualization but
for a local, homogeneous, cluster, it's less an issue.
By the way: In order to compensate for their "13%" degradation, I had to
nearly double the number of virtual nodes over real nodes to get the
same performance data. That's "expensive" but very do-able on a grid
environment.
gerry
--
Gerry Creager -- [EMAIL PROTECTED]
Texas Mesonet -- AATLT, Texas A&M University
Cell: 979.229.5301 Office: 979.862.3982 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843
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