Re: Uses for a cluster

Hi Evan!

> Our largest production cluster is a ~1000 node dual-xeon blade system.

I think you play in a different league... still if you need some 
processing load for your cluster feel free to ask ;-)

> We never purchase failover hardware because we always want to get the
> maximum system out there.  At any one time we might have 1 or 2 nodes
> out for maintenance, but that does not impact our running.

Actually, openmosix allows clusters without failover hardware (at least 
the damage is limited). I was thinking of the network infrastructure, or 
connectivity, be it Ethernet or whatever. These switches and Co can get 
really expensive, and if one fails, all your cluster is gone.

> Even though we have a large system, we have a mandatory 24hr runtime
> limit on our cluster systems because of stability.

Such a limit can be very useful. Maybe I should implement it into our 
environment, too. At the moment I have to restart after failures.

> What you describe as buying a single machine to save on cooling & power
> the industry buzz around here calls the 'price performance comparison'.
> Basically it's a marketing spreadsheet that says FLOPS per dollar of the
> entire solution of hardware/networking/storage/cooling/power (you
> provide your own people usually.

In fact, I just wanted to mention the availability of parallel computing 
platforms like the cell architecture as an alternative for certain 
applications.

> accomplish, obviously.  We have a few sun quad socket, DC machines and
> they start at 24k a piece!  The IBM, SGI, and SUN supermachine options
> are nice, but you can easily bust a million dollars on one rack.

I think it also depends on the manforce available to fix problems and 
the tolerance of the clients who need results. I can get a cheap cluster 
running, but if I had to give a warranty for results in time... Those 
supermachines are both expensive and high-quality (=stable and fixeable, 
service, documented, ...) imho. But I am sure Evan has much more 
experience with the different platforms.

> If you're going to stick to 'little' man you can get away with probably
> about 12-16 nodes before you have to really worry about cooling.

Here it depends on how little you are. If you even have no dedicated 
room, these things can get crucial. Looking at non-x86-platforms might 
make sense, again, for power consumption etc.

My response was directly connected to th "7 PCs" scenario. In general I 
doubt that seven standard PCs are a very useful setup for a 24/7 
cluster, so that explains my doubts. ;-) For experiments it is fine however.

CU Lars.


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