[awld]

Hi all,


I'm planning to purchase some hardware to run OpenFOAM simulations. These will be fairly small run-of-the-mill steady state RANS runs with grid sizes mostly below 1 million. However, there will be lots of these runs, i.e. many thousands. So this is less of an on-demand machine and more of a 24/7 number crunching device. Setup-wise, no regard needs to be placed on multi-user access.



Considering the small size of these runs, memory bandwidth is probably more important than CPU freq or core count. So, a dual Epyc configuration with 2x32 cores and 8 DDR3200 DIMMs per socket is my baseline, assuming that the sub-million grid point cases are never too large for this.


I've read up a lot on benchmarking and general setup, both in this board and elsewhere. With the background taken care of, I'd really appreciate some input regarding the following:

• Does my baseline make sense?
• Is is generally advisable to look at Epyc models with larger L3, i.e. 7532 (or 7543) versus 7452?

I'm looking at different ways to maximize throughput:

• Is there substantial benefit in going to a 2x64 core configuration? Obviously much more expensive, but I try to understand the options
• Is it maybe beneficial to go to multiple compute nodes with lower core counts (i.e. several of the 2x32 baseline boxes)?
• If so, what is the best system setup for these? Run them independently next to each other and do the coordination of runs via custom scripts, or set up a whole HPC environment with SLURM/PBS/whatnot controlled from a master node?

And finally some general points:

• As for general advice, any opinions on whether a tower or rack is better now and in the long run? I'm thinking about expandability, but maybe there are other factors. One could possibly add a storage solution to a rack, while this is more difficult with a tower.
• We are purchasing from Germany, any EU members on here able to offer advice on system integrators they had good experiences with?

That's a lot of questions. I'm aware that some of these are a matter of personal preference, but I'm looking for general input.


Any insight is much appreciated. Regards,
awld