Hi Steven, Dmytry Not sure if this web page is still valid or totally out of date, but there it goes anyway, in the hopes that it may help:
http://www.mcs.anl.gov/research/projects/mpi/mpich1-old/docs/install/node38.htm On the other hand, one expert seems to dismiss NFS for paralllel IO: http://www.open-mpi.org/community/lists/users/2008/07/6125.php I must say that this has been a gray area for me too. It would be nice if MPI - or the various MPIs - documentation told us a bit more clearly what types of underlying file system support MPI parallel IO: local disk (ext?, xfs, etc), NFS mounts, the various parallel file systems (PVFS/OrangeFS, Lustre, GlusterFS, etc). And perhaps provide some setup information, plus functionality, and performance comparisons. My two cents, Gus Correa On 11/07/2013 12:21 PM, Dmitry N. Mikushin wrote:
Not sure if this is related, but: I've seen a case of performance degradation on NFS and Lustre when writing NetCDF files. The reason was that the file was filled with a loop writing one 4-byte record at once. Performance became close to local hard drive, when I simply introduced buffering of records and writing them to files with one row at once. - D. 2013/11/7 Steven G Johnson<stev...@mit.edu>: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 ----------------------------------------------------------------------------------- #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; } _______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users_______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users
