[OMPI users] MPI_File_write hangs on NFS-mounted filesystem

[Steven G Johnson]

The simple C program attached below hangs on MPI_File_write when I am using an 
NFS-mounted filesystem.   Is MPI-IO supported in OpenMPI for NFS filesystems?

I'm using OpenMPI 1.4.5 on Debian stable (wheezy), 64-bit Opteron CPU, Linux 
3.2.51.   I was surprised by this because the problems only started occurring 
recently when I upgraded my Debian system to wheezy; with OpenMPI in the 
previous Debian release, output to NFS-mounted filesystems worked fine.

Is there any easy way to get this working?  Any tips are appreciated.

Regards,
Steven G. Johnson

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#include <stdio.h>
#include <string.h>
#include <mpi.h>

void perr(const char *label, int err)
{
    char s[MPI_MAX_ERROR_STRING];
    int len;
    MPI_Error_string(err, s, &len);
    printf("%s: %d = %s\n", label, err, s);
}

int main(int argc, char **argv)
{
    MPI_Init(&argc, &argv);

    MPI_File fh;
    int err;
    err = MPI_File_open(MPI_COMM_WORLD, "tstmpiio.dat", MPI_MODE_CREATE | 
MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
    perr("open", err);

    const char s[] = "Hello world!\n";
    MPI_Status status;
    err = MPI_File_write(fh, (void*) s, strlen(s), MPI_CHAR, &status);
    perr("write", err);

    err = MPI_File_close(&fh);
    perr("close", err);

    MPI_Finalize();
    return 0;
}