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  1. Hadoop Common
  2. HADOOP-14319

Under replicated blocks are not getting re-replicated

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Invalid
    • Affects Version/s: 2.7.2
    • Fix Version/s: None
    • Component/s: None
    • Labels:
      None
    • Target Version/s:
    • Tags:
      block replication

      Description

      Under replicated blocks are not getting re-replicated

      In production Hadoop cluster of 5 Manangement + 5 Data Nodes, under replicated blocks are not re-replicated even after 2 days.

      Here is quick view of required configurations;

      Default replication factor: 3
      Average block replication: 3.0
      Corrupt blocks: 0
      Missing replicas: 0 (0.0 %)
      Number of data-nodes: 5
      Number of racks: 1

      After bringing one of the DataNodes down, the replication factor for the blocks allocated on the Data Node became 2. It is observed that, even after 2 days the replication factor remains as 2. Under replicated blocks are not getting re-replicated to another DataNodes in the cluster.

      If a Data Node goes down, HDFS will try to replicate the blocks from Dead DN to other nodes and the priority. Are there any configuration changes to speed up the re-replication process for the under replicated blocks?

      When tested for blocks with replication factor 1, the re-replication happened to 2 overnight in around 10 hours of time. But blocks with 2 replication factor are not being re-replicated to default replication factor 3.

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            • Assignee:
              Unassigned
              Reporter:
              anil_tvns Anil

              Dates

              • Created:
                Updated:
                Resolved:

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