Re: I/O retardations (problems) in seward


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Posted by Evgeniy on November 27, 2009 at 17:46:09:

In Reply to: Re: I/O retardations (problems) in seward posted by Valera Veryazov on November 27, 2009 at 14:29:09:

:
: >I observe this on a big cluster which has a global scratch disk.

: If this global scratch disk is mounted as NFS, of course, I/O will be incredibly slow.
: Even if your system administrator claims that this global scratch area is fantastically fast - you MUST use local disks for WorkDir(s).
: If on your cluster there is no local hard disks (which is typical for e.g. BG solutions) - I am sorry, you have to find another computing system.


Thanks for your reply!
Unfortunately there are no local disks on the cluster nodes. But the global scratch disk has average rate ~500 MB/s. I am not sure but I think the problem was in a too small buffer size for CD. When I set VBUFfer to 1.0 I got increase by ~50-80 times. This supports the conjecture that I/O was effected only as for the seward module (as I wrote before even caspt2 which is very sensitive to I/O runs pretty fast).




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