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Subject: Re: [OMPI users] Parallel I/O with MPI-1
From: Robert Latham (robl_at_[hidden])
Date: 2008-07-24 09:19:31


On Wed, Jul 23, 2008 at 01:28:53PM +0100, Neil Storer wrote:
> Unless you have a parallel filesystem, such as GPFS, which is
> well-defined and does support file-locking, I would suggest writing to
> different files, or doing I/O via a single MPI task, or via MPI-IO.

I concur that NFS for a parallel I/O application should be avoided at
all costs. MPI-IO implementations do the best they can to function
correctly in the face of NFS challenges, but do so at a terrible cost
to performance.

There are several good parallel file systems available, both free and
commercial. No one in MPI-IO land should be stuck with NFS v3.

(there are many reasons to be hopeful that pNFS changes this story)

==rob

-- 
Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA                 B29D F333 664A 4280 315B