[Beowulf] Intro question

[Robert G. Brown]

On Tue, 2 Dec 2008, malcolm croucher wrote:

> Hi  Guys ,
> 
> I am still thinking about my cluster and most probably will only begin
> development next year june/july .
> 
> Question :
> 
> If i develop my system on  10 computers (nodes) which are all normal
> desktops and then would like to place this in data hosting facility which
> has access to real time information . I am going to need to buy new servers
> (thin 1 u servers ). Would this be the best choice as desktops take up more
> space and therefore will be more expensive . how do you guys get around this
> problem ? or dont you ?

I'm not sure I understand you, but let me try.

You plan to buy 10 computers to use for development of a cluster
application.  I presume that this means ten actual boxes, not a single
box with two quad core processors and a dual core or something like that
(my own choice for development would be no more than four machines, each
with one quad core processor or two dual core processors depending on
just where I expected to be internally bottlenecked, OR a single dual
quad).

Then you expect to place this in a data hosting facility -- basically
buy rack space and somebody to punch reset for you plus high speed
access to -- something you need in production but not in development.
Is that right?

The usual rule is that 1U nodes will cost a bit more than equivalently
equipped desktops, primarily because the 1U cases cost more and because
one has to work a bit harder to ensure that e.g. the CPUs stay cool and
so on.  I haven't checked marginal differences recently, but would
guestimate $250-500 per box.  This is a bit of a hit on ten boxes (if
that's what you plan on) but not a crazy one, and if you spend it up
front you a) have a MUCH smaller stack of systems in your house or
regular office -- ten 1U nodes in a stack is the size of a dorm
refrigerator, where ten minitowers stacked up is 2-3 times as much
space/volume -- then you don't have to buy new systems to move them into
your hosting facility rack, where they sell you space and where hosting
the towers -- if they let you put towers there at all -- will cost you
more on the far side.

To put it another way, I THINK that you should probably just get 1U
systems from the beginning, but there are so many variables you haven't
given us I can't be sure.  For example, your money or somebody else's?
Academic research or entrepreneurial?  HPC cluster or HA cluster?  Why
"ten nodes" -- a bit of an unusual number.  What are the relative costs
on the hosting side?  Would a much smaller system (like a single $3300
eight core dual quad) work just as well for prototyping, leaving you
with money later to buy as many 1U nodes as you need AFTER prototyping
and estimating capacity and so on?

    rgb

> 
> Regards
> 
> Malcolm
> 
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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