[Beowulf] Re: MS Cray

[Mark Hahn]

>  * Cluster people with significant constraints on space, power, or AC.

just space, really.  blade systems used to be almost unique in offering
high-efficiency power solutions, but I think most or all that's become 
available in the commodity market now.  (that is, 80-90% psu's in normal
1U servers).

and remember, less space and approximately the same power means higher 
heat-density.  I've never seen a lot of fully populated blade enclosures
in one spot (which is kinda the point), though it should be doable with 
rack-back heat exchangers.

actually, are there any blade systems that skip air-cooling entirely?
that would actually make sense - if you're going to go for bespoke power
because of potentially greater efficiency, bespoke cooling makes sense
for the same reason.

>  * businesses that want a turnkey system, typically for HA
> applications, that is compact and "easy" to support.

that part never made sense to me.  I'm skeptical that the management 
interface for blade systems is better than plain old IPMI.  prettier,
perhaps.

> And that is fair enough, actually.  Some places one literally has a
> closet to put one's cluster in, and if one populates the closet with a

a closet which just happens to have a huge jet of cold air going through it...

http://www.cray.com/Products/CX1/Product/Specifications.aspx
claims 1600W, 92% efficient.  their pages don't give much info on the 
engineering of the blades, though.  given that you have to add ipmi
as an option card, it looks pretty close to commodity parts to me.