[molpro-user] optimal HDD configuration for Molpro

Marcel Drabbels Marcel.Drabbels at epfl.ch
Mon Apr 30 16:16:54 BST 2007


We recently started using Molpro on our Opteron 
cluster. The high level MRCI calculations 
generate extensive disk I/O, making up most of 
the wall clock time. In order to speed up the 
system we ideally would upgrade our IDE disks to 
SCSI disks. However, due to financial constraints 
this is not feasible. In stead we plan to add a 
second hard drive to our computational nodes. The 
question that I now have is the following: 
what  is the optimal HDD configuration for Molpro 
in terms of speed. Is it better to use the two 
HDD's in a software RAID 0 configuration or use 
two HDD as separate scratch directories using the 
-d option in Molpro?  In addition I would 
appreciate you input on what is the best 
(fastest) file system for this type of job. My 
guess would be that a non-journaling system like 
EXT2 should be faster than a journaling sytem.

Any suggestions on how to make our system fly are welcome.

Best regards, Marcel

Dr. Marcel Drabbels
Laboratoire de Chimie Physique Moléculaire (LCPM)
École Polytechnique Fédérale de Lausanne (EPFL)
Station 6
CH-1015 Lausanne

Tel: +41-21-693 3022/6131
Fax: +41-21-693 5170

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