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  1. Lustre
  2. LU-13287

DNE2 - Shared directory performance does not scale and starts to plateau beyond 2MDTs

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Details

    • Improvement
    • Resolution: Not a Bug
    • Major
    • None
    • Lustre 2.13.0
    • 9223372036854775807

    Description

      While testing in an environment with a single parent directory following by 1 shared sub directory for all client mdtest ranks, we are observe very little scaling when moving to more than 2 MDTs. See below for 1 million objects per MDT, 0K File Creates:

      1 MDTs - 83,948
      2 MDTs - 115,929
      3 MDTs - 123,186
      4 MDTs - 130,846

      Stats and deletes are showcasing similar results. It seems to not follow a linear scale but instead plateaus. It would also seem that we are not the only ones to observe this. A recent Cambridge University IO-500 presentation presented a slide with very similar results (fourth from the bottom): https://www.eofs.eu/_media/events/lad19/03_matt_raso-barnett-io500-cambridge.pdf

      Attachments

        1. archive_smaller_inodes-tests.pptx
          627 kB
          Petros Koutoupis
        2. archive_smaller_inodes-tests.tar.gz
          166 kB
          Petros Koutoupis
        3. Screen Shot 2020-02-21 at 16.11.52.png
          64 kB
          Andreas Dilger
        4. shared-directory_mdt-perf.tar.gz
          6.78 MB
          Petros Koutoupis

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              wc-triage WC Triage
              koutoupis Petros Koutoupis
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                Updated:
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