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  1. Lustre
  2. LU-5212

poor stat performance after upgrade from zfs-0.6.2-1/lustre-2.4.0-1 to zfs-0.6.3-1

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Details

    • Bug
    • Resolution: Won't Fix
    • Minor
    • None
    • Lustre 2.4.2
    • centos 6.5

    Description

      After upgrading a system from
      lustre 2.4.0-1 / zfs-0.6.2-1 to
      lustre 2.4.2-1 / zfs-0.6.3-1

      mdtest shows a signficantly lower stat performance - about 8000 iops vs 14400

      File reads and file removals are a bit worse, but not as severe. See the attached graph.

      We do see other marked improvements with the upgrade, for example with system processes waiting on the MDS.

      I wonder if this is some kind of expected perfromance tradeoff for the new version? I'm guessing the absolute numbers for stat are still acceptable for our workload, but it is quite a large relative difference.

      Scott

      Attachments

        1. mdtest-zfs063.png
          mdtest-zfs063.png
          15 kB
        2. arcstat-1.png
          arcstat-1.png
          11 kB
        3. arcstat-2.png
          arcstat-2.png
          12 kB
        4. arcstat-3.png
          arcstat-3.png
          14 kB
        5. arcstat-MB.png
          arcstat-MB.png
          11 kB
        6. arcstat-2-95G-arc_meta_limit.png
          arcstat-2-95G-arc_meta_limit.png
          13 kB
        7. arcstat-95G-arc_meta_limit.png
          arcstat-95G-arc_meta_limit.png
          10 kB
        8. mdtest-zfs063-95G-arc_meta_limit.png
          mdtest-zfs063-95G-arc_meta_limit.png
          17 kB

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              wc-triage WC Triage
              sknolin Scott Nolin (Inactive)
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                Updated:
                Resolved: