Open MPI doesn't really do much file IO at all. We do a little during startup / shutdown, but during the majority of the MPI application run, there's little/no file IO from the MPI layer.
Note that the above statements assume that you are not using the MPI IO function calls. If your application is using MPI IO, then of course, Open MPI will do lots of file IO.
My point: if your application isn't doing MPI IO, then your file IO is likely coming from somewhere other than Open MPI.
On Oct 25, 2012, at 2:51 PM, Mahmood Naderan wrote:
> I sent a problem to the list but didn't receive any reply. In short, we found
> that when we run openmpi+openfoam program on a node (in a diskless cluster),
> there is a huge IO operations caused by openmpi. When we run openmpi+openfoam
> on the server, there is no problem. When we run openfoam directly on the node,
> there is also no problem.
> Now I am looking for some verbose/debug outputs from openmpi which
> shows the activity of it (in particular IO messages for example opening file1
> or closing file2...).
> Can I extract such messages?
> From: Ralph Castain <rhc_at_[hidden]>
> To: Mahmood Naderan <nt_mahmood_at_[hidden]>; Open MPI Users <users_at_[hidden]>
> Sent: Thursday, October 25, 2012 8:44 PM
> Subject: Re: [OMPI users] running openmpi in debug/verbose mode
> There is a *ton* of debug output available - would help to know what you are attempting to debug
> On Oct 25, 2012, at 11:38 AM, Mahmood Naderan <nt_mahmood_at_[hidden]> wrote:
>> Dear all,
>> Is there any way to run openmpi in debug or verbose mode? Is there any log for openmpi run?
>> users mailing list
> users mailing list
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