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

Reto,

I should have also pointed out that the output of the program you attached was

 *** SUCCESS writing example file simple_xy_par.nc! 

even if I commented out the line that forced independent writes by calling

  nf90_var_par_access(ncid, varid, nf90_independent)

Also, for your information, another user has recently reported a bug in the
implementation of nf90_var_par_access when used with parallel-netcdf:

  http://www.unidata.ucar.edu/support/help/MailArchives/netcdf/msg11678.html

--Russ

> 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
> 
> 
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