Registered Member #5726
Joined Sun Apr 22 2012, 08:45AM
posts 4
Dear Colleagues,
We are currently in the process of building a cluster, which will be mainly used for VASP simulations. Those include both DFT and hybrid-DFT, GW and NEB simulations.
I would like to ask your advice regarding the appropriate hardware:
The head node: two eight-core Intel Xeon E5-2650 processors, 64 GB memory, and two 300GB SAS disks.
Computing nodes: eight-core Intel Xeon E5-2650, 64GB memory, 2TB SATA disk.
What would be appropriate for the scratch, SDD, HDD drive?
Registered Member #47
Joined: Tue Nov 16 2004, 02:21PM
Location: Germany
posts 365
Hello Monica,
some experiences:
Memory:
- for plain DFT ~1 GB/core is sufficient. If your calculation gets larger, use more cores. Scaling is still good.
- Hybrid DFT is more demanding. If I do such calculations (sometimes only), I go for, e.g. only half the cores per box using full memory
- GW: no idea about that.
CPUs:
You might wish to consider AMD Opteron also. Check SpecFP rates to get a proper comparison with Intel. Better: Ask your local dealer for two test sets. It might save quite a bit of money! I'm very happy with a 8C 2.2 GHz Opteron. In my experience 12C was worse than 8C, because they have the same number of memory channels/interfaces. So the performance dropped dramatically (30-50%) with even only medium sized (~100 atoms) systems. One thing to check!
Scratch:
In my experience (DFT and hybrid DFT) this is no issue. I'm going along with some cheap HDD. VASP does not write large files on a regular basis (except you ask for it), because the performance would break down. Again: No idea about GW though ...
Network:
Get anything which is faster (better: lower latency) than GBit! This is really an issue. Infiniband or Myrinet is good. I never tried 10GBit Ethernet (the cost of the switch was astronomical at the time of my last purchase).
Cheers,
alex
PS: I've got a bunch of 2x AMD Opteron 8C 2.2 GHz, 32 GB memory, 2 HDD (160 GB) for RAID1 and Infiniband (cheapest card available). The machine is called HP BL465c G7. Server is similar, but more HDD and memory, but no IB network.