The reason LUMI is advising against many files is that it uses the Lustre parallel filesystem, which is notoriously bad with small files. See here: https://www.

The reason LUMI is advising against many files is that it uses the Lustre parallel filesystem, which is notoriously bad with small files. See here: https://www.lanl.gov/projects/national-security-education-center/information-science-technology/_assets/docs/2021-si-docs/booher-kulkarni-lustre-DNE.pdf https://www.lanl.gov/projects/national-security-education-ce... .