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Cray Lmod setup

2 versions of LMOD

Since the October-November 2023 update there are two versions of LMOD on the system

  1. A version installed in the system directories, likely one that comes with SUSE linux.

    • In November 2023 this is LMOD 8.3.1.
    • Installation directory: /usr/share/lmod/

  2. A version installed with the PE.

    • In November 2023 this is LMOD 8.7.19 which comes with the 23.09 PE.
    • Installation directory: /opt/cray/pe/lmod

The active one after login is the one the comes with the HPE Cray PE, so when re-initialising be sure to call the initialisation functions of that version of LMOD.

Problems

  • module spider does not work correctly. It does not always show all possible combinations to access a module. This is because the HPE Cray PE doesn't use hierarchies as intended by the LMOD developer. Sometimes a combination of two other modules loaded in any order triggers a change to MODULEPATH.

  • Noise about problems with the cache. We do note occasional cache problems on LUMI but those don't seem to be associated with specific properties of the HPE Cray PE Lmod setup but rather with the system not detecting that modules have been added to the tree. I guess Linux with Lustre may have no notification system to detect the moment of change in a subdirectory to see if a cache file is still valid and to ignore (system cache) or regenerate (user cache) it otherwise.