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