[Wrf-users] Parallel NETCDF4?

Wei-keng Liao wkliao at eecs.northwestern.edu
Sat Mar 5 05:16:05 MST 2016


Hi, Chris

The file size difference may be due to data compression when WRF uses HDF5
library internally to write NetCDF4 files. PnetCDF does not do compression.
You can use "ncgen" to convert a netCDF classical file to netCDF conformed
HDF5 files. See netCDF user guide for command-line options of ncgen.
http://www.unidata.ucar.edu/software/netcdf/docs/netcdf_utilities_guide.html#guide_ncgen

As for the files produced by PnetCDF, would you mind answering my
2 questions. Were you writing the outputs to a Lustre file system,
or the name of parallel file system you used if not Lustre?
What version of WRF are you using?

Wei-keng

On Mar 4, 2016, at 3:54 AM, Christopher Thomas wrote:

> Hi there,
> 
> Does anyone know how to compile WRF to use parallel NETCDF but still output NETCDF4 files? 
> 
> I am using 512 cores and outputting data at high temporal and spatial resolutions; parallel NETCDF reduces my wall times by about 1/3 but more than doubles output file sizes over NETCDF4 serial output.
> 
> Chris 
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