[Beowulf] cloud: ho hum?

Mark Hahn hahn at mcmaster.ca
Wed Feb 1 07:08:24 PST 2012

in hopes of leaving the moderation discussion behind, 
here's a more interesting topic: cloud wrt beowulf/hpc.

when I meet cloud-enthused people, normally I just explain how 
HPC clustering has been doing PaaS cloud all along.  there are some
people who run with it though: bioinformatics people mostly, who 
take personal affront to the concept of their jobs being queued.
(they don't seem to understand that queueing is a function of how
efficiently utilized a cluster is, and since a cloud is indeed a 
cluster, you get queueing in a cloud as well.)

part of the issue here seems to be that people buy into a couple 
fallacies that they apply to cloud:
 	- private sector is inherently more efficient.  this is a bit
 	of a mystery to me, but I guess this is one of the great rhetorical
 	successes of the neocon movement.  I've looked at Amazon prices,
 	and they are remarkably high - depending on purchasing model,
 	about 20x higher than an academic-run research cluster.  why is there
 	not more skepticism of outsourcing, since it always means your cost
 	includes one or more corporate profit margins?

 	- economies of scale: people seem to think that a datacenter at the
 	scale of google/amazon/facebook is going to be dramatically cheaper.
 	while I'm sure they get a good deal from their suppliers, I also
 	doubt it's game-changing.  power, for instance, is a relatively
 	modest portion of costs, ~10% per year of a server's purchase price.
 	machineroom cost is pretty linear with number of nodes (power);
 	people overhead is very small (say, > 1000 servers per fte.)

most of all, I just don't see how cloud changes the HPC picture at all.
HPC is already based on shared resources handling burstiness of demand - 
if anything, cloud is simply slower.  certainly I can't submit a job to 
EC2 that uses half the Virgina zone and expect it to run immediately.
it's not clear to me whether cloud-pushers are getting real traction with
the funding agencies (gov is neocon here in Canada.)  it worries me that 
cloud might be framed as "better computing than HPC".

I'm curious: what kind of cloudiness are you seeing?

thanks, mark hahn.

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