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  1. Hadoop HDFS
  2. HDFS-6425

Large postponedMisreplicatedBlocks has impact on blockReport latency

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 2.7.0
    • Component/s: namenode
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      Sometimes we have large number of over replicates when NN fails over. When the new active NN took over, over replicated blocks will be put to postponedMisreplicatedBlocks until all DNs for that block aren't stale anymore.

      We have a case where NNs flip flop. Before postponedMisreplicatedBlocks became empty, NN fail over again and again. So postponedMisreplicatedBlocks just kept increasing until the cluster is stable.

      In addition, large postponedMisreplicatedBlocks could make rescanPostponedMisreplicatedBlocks slow. rescanPostponedMisreplicatedBlocks takes write lock. So it could slow down the block report processing.

        Attachments

        1. HDFS-6425.patch
          20 kB
          Ming Ma
        2. HDFS-6425-2.patch
          18 kB
          Ming Ma
        3. HDFS-6425-3.patch
          14 kB
          Ming Ma
        4. HDFS-6425-Test-Case.pdf
          42 kB
          Ming Ma

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              • Assignee:
                mingma Ming Ma
                Reporter:
                mingma Ming Ma
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                • Created:
                  Updated:
                  Resolved: