# MPI error: \`'xios::CNetCdfException' ... NetCDF: Parallel operation on file opened for non-parallel access\`
**URL:** https://nemo-ocean.discourse.group/t/mpi-error-xios-cnetcdfexception-netcdf-parallel-operation-on-file-opened-for-non-parallel-access/176
**Category:** Versions
**Tags:** XIOS, IOM, deps
**Created:** [12 January 2022 10:42 UTC](https://nemo-ocean.discourse.group/t/mpi-error-xios-cnetcdfexception-netcdf-parallel-operation-on-file-opened-for-non-parallel-access/176 "2022-01-12T10:42:02Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Jin](https://nemo-ocean.discourse.group/u/Jin)
#### Post date: [12 January 2022 10:42 UTC](https://nemo-ocean.discourse.group/t/mpi-error-xios-cnetcdfexception-netcdf-parallel-operation-on-file-opened-for-non-parallel-access/176/1 "2022-01-12T10:42:02Z")
Dear all,
Hello, I met some problems when running ORCA2\_ICE\_PISCES.
When I try to use MPI I receive the following message (details are below):
```nohighlight
"terminate called after throwing an instance of 'xios::CNetCdfException'
what(): Error when calling function: nc_create_par(fileName.c_str(), cMode, comm, info, &ncId)
NetCDF: Parallel operation on file opened for non-parallel access"
```
Does anyone know how to fix it?
There was no `E R R O R` flag in _ocean.output_ and _time.step_ was 76.
My arch file
```perl
%NCDF_HOME /usr/lib/x86_64-linux-gnu
%HDF5_HOME /usr/lib/x86_64-linux-gnu/hdf5/serial
%XIOS_HOME /media/cmlws/Data1/hjc/xios-2.5
%OASIS_HOME /not/defined
#%NCDF_INC -I%NCDF_HOME/include -I%HDF5_HOME/include
%NCDF_INC -I%NCDF_HOME -I%HDF5_HOME/include
%NCDF_LIB -L%NCDF_HOME -lnetcdff -lnetcdf -lstdc++
%XIOS_INC -I%XIOS_HOME/inc
%XIOS_LIB -L%XIOS_HOME/lib -lxios -L/usr/lib/gcc/x86_64-linux-gnu/9 -lstdc++
%OASIS_INC -I%OASIS_HOME/build/lib/mct -I%OASIS_HOME/build/lib/psmile.MPI1
%OASIS_LIB -L%OASIS_HOME/lib -lpsmile.MPI1 -lmct -lmpeu -lscrip
%CPP /usr/bin/cpp-9 -Dkey_nosignedzero
%CPPFLAGS -P -traditional
%FC /usr/bin/mpif90
%FCFLAGS -fdefault-real-8 -funroll-all-loops -cpp -fcray-pointer -ffree-line-length-none -g -O0 -fbacktrace -fbounds-check
%FFLAGS %FCFLAGS
#%LD /usr/bin/mpif90 -Wl,-rpath=$HOME/INSTALL/lib:/usr/lib
%LD /usr/bin/mpif90
%LDFLAGS -L/usr/lib/x86_64-linux-gnu
%FPPFLAGS -P -C -traditional
%AR ar
%ARFLAGS -rs
%MK make
%USER_INC %XIOS_INC %OASIS_INC %NCDF_INC
%USER_LIB %XIOS_LIB %OASIS_LIB %NCDF_LIB
%CC gcc
%CFLAGS -O0 -fbacktrace
```
Summarized mpirun log :
```nohighlight
Fortran runtime warning: Namelist object 'clname' truncated on read.
At line 103 of file /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/tideini.f90 (unit = 16, file = 'namelist_ref')
Backtrace for this error:
terminate called after throwing an instance of 'xios::CNetCdfException'
what(): Error when calling function: nc_create_par(fileName.c_str(), cMode, comm, info, &ncId)
NetCDF: Parallel operation on file opened for non-parallel access
Unable to create file on parallel file system, given its name:
and its creation mode In the composed creation mode
Program received signal SIGABRT: Process abort signal.
#47 0x55dccd27cb17 in __sbcssm_MOD_sbc_ssm
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/sbcssm.f90:218
#47 0x5629c49ceb17 in __sbcssm_MOD_sbc_ssm
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/sbcssm.f90:218
#46 0x55cdb1a5c001 in __iom_MOD_iom_p2d
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/iom.f90:1693
#47 0x55cdb0e4bb17 in __sbcssm_MOD_sbc_ssm
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/sbcssm.f90:218
#48 0x5629c497f679 in __sbcmod_MOD_sbc
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/sbcmod.f90:452
#49 0x5629c49ffc02 in __step_MOD_stp
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/step.f90:138
#50 0x5629c495cb01 in __nemogcm_MOD_nemo_gcm
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/BLD/ppsrc/nemo/nemogcm.f90:192
#51 0x5629c4957f11 in nemo
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/WORK/nemo.f90:18
#52 0x5629c4957f4a in main
at /media/cmlws/Data1/hjc/NEMO/r4.0.6/cfgs/ORCA_testing3/WORK/nemo.f90:11
```
1693 line in _iom.f90_: `CALL xios_send_field(cdname, pfield2d)`
```fortran
SUBROUTINE iom_p2d( cdname, pfield2d )
CHARACTER(LEN=*) , INTENT(in) :: cdname
REAL(wp), DIMENSION(:,:), INTENT(in) :: pfield2d
CALL xios_send_field(cdname, pfield2d)
END SUBROUTINE iom_p2d
```
the last part of _ocean.output_:
```nohighlight
fld_read: var dust kt = 76 ( 4.7188 days), Y/M/D = 0001/01/05, records b/a: 0012/ 0001 (days -15.5000/ 15.5000)
it_offset is : 0
fld_read: var riverdic kt = 76 ( 4.7188 days), Y/M/D = 0001/01/05, records b/a: 0001/ 0002 (days 2.5000/ 7.5000)
it_offset is : 0
fld_read: var riverdoc kt = 76 ( 4.7188 days), Y/M/D = 0001/01/05, records b/a: 0001/ 0002 (days 2.5000/ 7.5000)
it_offset is : 0
fld_read: var riverdin kt = 76 ( 4.7188 days), Y/M/D = 0001/01/05, records b/a: 0001/ 0002 (days 2.5000/ 7.5000)
it_offset is : 0
fld_read: var riverdon kt = 76 ( 4.7188 days), Y/M/D = 0001/01/05, records b/a: 0001/ 0002 (days 2.5000/ 7.5000)
```
Thank you in advance.
Best regards,
Hwa-Jin Choi
---
### Author:  [@acc](https://nemo-ocean.discourse.group/u/acc)
#### Post date: [12 January 2022 12:43 UTC](https://nemo-ocean.discourse.group/t/mpi-error-xios-cnetcdfexception-netcdf-parallel-operation-on-file-opened-for-non-parallel-access/176/2 "2022-01-12T12:43:13Z")
Hi Hwa-Jin, The clue is probably this:
```perl
%HDF5_HOME /usr/lib/x86_64-linux-gnu/hdf5/serial
```
You will need to use an HDF5/NetCDF4 combination that has been compiled with parallel IO support if you want to use the full functionality of XIOS.
The details should be under:
[https://forge.ipsl.jussieu.fr/nemo/chrome/site/doc/NEMO/guide/html/install.html](https://forge.ipsl.jussieu.fr/nemo/chrome/site/doc/NEMO/guide/html/install.html)
From memory, it means making sure HDF5 was built with `--enable-parallel`.
---
### Author:  [@Jin](https://nemo-ocean.discourse.group/u/Jin)
#### Post date: [17 January 2022 07:39 UTC](https://nemo-ocean.discourse.group/t/mpi-error-xios-cnetcdfexception-netcdf-parallel-operation-on-file-opened-for-non-parallel-access/176/3 "2022-01-17T07:39:38Z")
Thank you very much for your answer.
I recompiled the HDF5/NetCDF4 with MPI.
Successfully done!!! 😍
Thank you again for your help.
Best regards,
Hwa-Jin Choi