clusters v SMP

[Schilling, Richard]

Sounds like you're wanting to run canned software. 

You have a couple of key things to look at, and the final decision depends
on user needs and how much money you'll have in the future, as well as
current/future staffing.  You'll probably find that a good SMP machine
costs less time to set up, but is more difficult to migrate away from.  A
beowulf, PC grade cluster, takes longer time to set up and configure, but
you'll have greater flexibility later on.

My advice would be to *not* make a *complete* commitment to either
approach.  Remember, a beowulf-class machine can be made out of any
collection of machines, including one or more SMP machines.  So, if you
play your cards correctly, you could in theory get a few good SMP machines
for general purpose processing, and give them the dual role of serving as a
bewoulf-class cluster.  Or at least you should be able to buy a couple of
good SMP machines, a few commodity PCs and build a really nice cluster.

If you're forced to choose, consider this: centralized production systems,
for batch file job processing and nightly updates (e.g. business production
jobs), tend to favor SMP at this point because the software base is more
robust and doesn't take as long to set up.  Carefully scrutenize any vendor
that has a prepackaged "cluster friendly" application.

The Compaq Alpha architecutre (formerly DEC), with their clustered
application servers, are a good compromise between the two choices.  The
topology is proprietary, but they are high availability and run very well.
For $300,000 you can certainly get into some nice Alpha hardware and a
support contract.


Richard Schilling
Webmaster / Web Integration Programmer
Affiliated Health Services
Mount Vernon, WA USA
http://www.affiliatedhealth.org
phone: 360.856.7129


> -----Original Message-----
> From: William Park [mailto:opengeometry at yahoo.ca]
> Sent: Monday, January 28, 2002 1:27 PM
> To: beowulf at beowulf.org
> Subject: Re: clusters v SMP
> 
> 
> On Mon, Jan 28, 2002 at 08:11:51PM +0000, Ricky Rankin wrote:
> > At Queen's we hope to have abot ?300K to spend on a new facility. We
> > currently have a Sun 3500 with 6 processors and 6GB of 
> memory and a 48
> > Node IBM SP.
> > 
> > At one stage we had thought that the budget would be around 
> ?150K and
> > had been looking for a Linux Cluster, however with more money
> > potentially available and having had presentations from IBM and SGI
> > with Sun and Compaq to follow we are now completely confused.
> 
> Hehe... know the feeling.
> 
> > 
> > The 4GB memory restriction of an Intel node would be too restrictive
> > for some of our users. The majority I suspect are still 
> running single
> > processor jobs while we have several users who can exploit parallel
> > architectures.
> > 
> > Some advice on the pros and cons of the different 
> architectures would
> > be appreciated - we are looking for a central production system and
> > not one that is owned by a department.
> > 
> > Thanks Ricky
> 
> SMP is always better than clusters, but you can add more CPUs to your
> clusters.  Why not get a quad (or few duals) with globs of RAM?  That
> would satisfy both the single-cpu users and multi-cpu users.  
> Last time
> I checked, anything more than 4-way was too expensive.  But, then, I
> didn't have someone else to pay for it. :-)
> 
> -- 
> William Park, Open Geometry Consulting, <opengeometry at yahoo.ca>
> 8 CPU cluster, NAS, (Slackware) Linux, Python, LaTeX, Vim, Mutt, Tin
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