Question about custers

[Robert G. Brown]

On Fri, 7 Feb 2003, Ken Chase wrote:

> On Fri, Feb 07, 2003 at 07:25:31PM +0100, KNT's all...
> > I'm only interested in calculating it theoretical (simple: on paper, no
> > computers used). Because it's needed for me to esteminate the power of a
> > non-existent cluster. I thought that the difference between
> > 'theoretical' and 'practical' will be obvious. My mistake.
> > 
> > About 'power': I don't know an apropriate word in english for "computer
> > mathematical calculation ability" ;).
> 
> The difference between 'fastest speed for single job execution' and
> 'number of jobs throughput per month' call for quite different cluster
> configurations for the money.
> 
> Realistically I believe most people require the latter, but for some reason
> (bragging rights? impressing lay people?) the former is always sought
> after. Anyone care to comment?

My only modifications of this are that you might add "per dollar spent"
and refer to "total work done" rather than number of jobs per se.  Some
people might run only a single job per month, but be very interested in
the size or total amount of work that job could get done by some other
measure.

Without the connection of money and cost benefit analysis, of course one
gets the fastest possible nodes and so forth.  It's only when one looks
at the amount of work one can get done for your fixed budget that one
suddenly realizes that one can buy a very nice complete 2.4 GHz P4
compute node for what one pays for a 3.0 GHz P4 CPU alone.

CBA is the key to happy cluster design.  Spend your money getting what
you need to get the most work done in the least amount of time, for your
budget.

Unless, of course, you are backed by the full buying power of the U.S.
Government, in which case you get whatever you damn well please...:-)

   rgb

Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu