# Xios : diamlr output not working in parrallel

**URL:** <https://nemo-ocean.discourse.group/t/xios-diamlr-output-not-working-in-parrallel/993>\
**Category:** v4.2.x\
**Tags:** XIOS\
**Created:** [26 February 2026 19:04 UTC](https://nemo-ocean.discourse.group/t/xios-diamlr-output-not-working-in-parrallel/993 "2026-02-26T19:04:45Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![gdenoordhout](https://avatars.discourse-cdn.com/v4/letter/g/bbe5ce/32.png) [@gdenoordhout](https://nemo-ocean.discourse.group/u/gdenoordhout)\
**Post date:** [26 February 2026 19:04 UTC](https://nemo-ocean.discourse.group/t/xios-diamlr-output-not-working-in-parrallel/993/1 "2026-02-26T19:04:45Z")

</div>

Dear all,

I am currently running a NEMO4.2.1 configuration on the North Sea (based on AMM7 developed by the Met Office). For my tidal analysis, I activated the diamlr output (regrouping all the regressors for each tidal component). When running the configuration in detached mode (using Xios server) with one cpu on Xios, everything works find (except that the simulation is very slow). If I try to increase the number of cpus on Xios, I get an error in the log file :

terminate called after throwing an instance of ‘xios::CNetCdfException’  
terminate called after throwing an instance of ‘xios::CNetCdfException’  
what(): what(): Error when calling function nc\_enddef(ncId)  
NetCDF: HDF error  
Unable to end define mode of this file, given its id: 1507328

Program received signal SIGABRT: Process abort signal.

Backtrace for this error:  
Error when calling function nc\_enddef(ncId)  
NetCDF: HDF error  
Unable to end define mode of this file, given its id: 1769472

Has anyone ever encoutered this problem ?

Thank you for your help,

Guillaume