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[netCDF #TIR-820282]: NetCDF-4 Parallel independent access with unlimited dimension (Fortran 90)

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  • Subject: [netCDF #TIR-820282]: NetCDF-4 Parallel independent access with unlimited dimension (Fortran 90)
  • Date: Tue, 09 Apr 2013 15:01:33 -0600
Hi Reto,

Sorry to have taken so long to respond to your question.
> I have been using NetCDF-4 Parallel I/O with the Fortran 90 interface for 
> some time with success. Thank you for this great tool!
> 
> However, I now have an issue with independent access:
> 
> - NetCDF F90 Parallel access (NetCDF-4, MPIIO)
> - 3 fixed and 1 unlimited dimension
> - alle processes open/close the file and write metadata
> - only a few processes write to the file (-> independent access)
> - the write hangs. It works fine if all processes take place.
> 
> I've changed your example F90 parallel I/O file simple_xy_par_wr.f90 to 
> include a unlimited dimension and independent access of only a subset of 
> processes. Same issue. Even if I explicitly set the access type to 
> independent for the variable. Can you reproduce the issue on your side?
> 
> The following system configuration on my side:
> - NetCDF 4.2.1.1 and F90 interface 4.2
> - hdf5 1.8.9
> - Openmpi 1.
> - OSX, gcc 4.6.3

No, I haven't been able to reproduce the issue, but I can't exactly duplicate
your configuration easily, and there have been some updates and bug fixes that
may have made a difference.

First I tried this configuration, which worked fine on your attached example:

 - NetCDF 4.3.0-rc4 and F90 interface 4.2
 - hdf5 1.8.11 (release candidate from svn repository)
 - mpich2-1.3.1
 - Linux Fedora, mpicc, mpif90 wrapping gcc, gfortran 4.5.1

So if you can build those versions, it should work for you.  I'm not sure 
whether
the fix is in netCDF-4.3.0 or in hdf5-1.8.11, but both have a fix for at least 
one
parallel I/O hanging process issue:

  https://bugtracking.unidata.ucar.edu/browse/NCF-214  (fix in netCDF-4.3.0)
  https://bugtracking.unidata.ucar.edu/browse/NCF-240  (fix in HDF5-1.8.11)

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: TIR-820282
Department: Support netCDF
Priority: High
Status: Closed