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  1. Cassandra
  2. CASSANDRA-8329

LeveledCompactionStrategy should split large files across data directories when compacting

    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Fix Version/s: 2.0.12, 2.1.3
    • Component/s: Compaction
    • Labels:

      Description

      Because we fall back to STCS for L0 when LCS gets behind, the sstables in L0 can get quite large during sustained periods of heavy writes. This can result in large imbalances between data volumes when using JBOD support.

      Eventually these large files get broken up as L0 sstables are moved up into higher levels; however, because LCS only chooses a single volume on which to write all of the sstables created during a single compaction, the imbalance is persisted.

        Attachments

        1. test_with_patch_2.0.jpg
          109 kB
          Alan Boudreault
        2. test_no_patch_2.0.jpg
          103 kB
          Alan Boudreault
        3. 0001-get-new-sstable-directory-for-every-new-file-during-.patch
          10 kB
          Marcus Eriksson

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              • Assignee:
                krummas Marcus Eriksson
                Reporter:
                jblangston@datastax.com J.B. Langston
                Reviewer:
                Yuki Morishita
                Tester:
                Alan Boudreault
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                Dates

                • Created:
                  Updated:
                  Resolved: