Uploaded image for project: 'Hadoop HDFS'
  1. Hadoop HDFS
  2. HDFS-4093

In branch-1-win, AzureBlockPlacementPolicy#chooseTarget only returns one DN when replication factor is greater than 3.

    XMLWordPrintableJSON

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 1-win
    • Component/s: None
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      In branch-1-win, when AzureBlockPlacementPolicy (which extends the BlockPlacementPolicyDefault) is used, if the client increases the number of replicas (e.g., from 3 to 10), AzureBlockPlacementPolicy#chooseTarget will return only 1 Datanode each time. Thus in FSNameSystem#computeReplicationWorkForBlock, it is possible that the replication monitor may choose a datanode that has been chosen as target but still in the pendingReplications (because computeReplicationWorkForBlock does not check the pending replication before doing the chooseTarget).

      To avoid this "hit-the-same-datanode" scenario, we modify the AzureBlockPlacementPolicy#chooseTarget to make it return multiple DN.

        Attachments

        1. HDFS-b1-win-4093.002.patch
          6 kB
          Jing Zhao
        2. HDFS-b1-win-4093.001.patch
          5 kB
          Jing Zhao

          Activity

            People

            • Assignee:
              jingzhao Jing Zhao
              Reporter:
              jingzhao Jing Zhao
            • Votes:
              0 Vote for this issue
              Watchers:
              3 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: