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Subject: Re: [OMPI users] a question about [MPI]IO on systems without network filesystem
From: Terry Frankcombe (terry_at_[hidden])
Date: 2010-09-29 21:47:06


Hi Paul

I think you should clarify whether you mean you want you application to
send all it's data back to a particular rank, which then does all IO (in
which case the answer is any MPI implementation can do this... it's a
matter of how you code the app), or if you want the application to know
nothing about it, but have the system somehow intercept all IO and make
it magically appear at a particular node (much harder).

On Wed, 2010-09-29 at 11:34 +0200, Paul Kapinos wrote:
> Dear OpenMPI developer,
>
> We have a question about the possibility to use MPI IO (and possible
> regular I/O) on clusters which does *not* have a common filesystem
> (network filesystem) on all nodes.
>
> A common filesystem is mainly NOT a hard precondition to use OpenMPI:
> http://www.open-mpi.org/faq/?category=running#do-i-need-a-common-filesystem
>
>
> Say, we have a (diskless? equipped with very small disks?) cluster, on
> which only one node have access to a filesystem.
>
> Is it possible to configure/run OpenMPI in a such way, that only _one_
> process (e.g. master) performs real disk I/O, and other processes sends
> the data to the master which works as an agent?
>
> Of course this would impacts the performance, because all data must be
> send over network, and the master may became a bottleneck. But is such
> scenario - IO of all processes bundled to one process - practicable at all?
>
>
> Best wishes
> Paul
>
>
>
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