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  1. Cassandra
  2. CASSANDRA-14587

TrueDiskSpaceUsed overcounts snapshots

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    Details

    • Type: Bug
    • Status: Open
    • Priority: Low
    • Resolution: Unresolved
    • Fix Version/s: None
    • Component/s: Tool/nodetool
    • Labels:
      None
    • Environment:

      Debian 8

      Cassandra 3.11.2

    • Severity:
      Low

      Description

      Running 'nodetool listsnapshots' seems to overcount "TrueDiskSpaceUsed" under some circumstances.  Specifically when there's a large number of snapshots.  I suspect that it's not deduplicating space used when multiple snapshots share sstables that are not part of the current table.

      Results of "nodetool listsnapshots":
      Total TrueDiskSpaceUsed: 396.11 MiB
      Results of "du -hcs" on the table's directory:
      18M    total

      This is 50+ snapshots (every minute) run with "-t <datestamp> -sf --column-family <tablename> <keyspace>"
      The results of a "du -hcs -L <directory" come out pretty close to the "TrueDiskSpaceUsed"

      I have only tested against 3.11.2, but have no reason to believe it's unique to that version or even 3.x.

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            • Assignee:
              e.dimitrova Ekaterina Dimitrova
              Reporter:
              Defenestrator Elliott Sims
              Authors:
              Ekaterina Dimitrova
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              Dates

              • Created:
                Updated: