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  1. Hadoop HDFS
  2. HDFS-9044

Give Priority to FavouredNodes , before selecting nodes from FavouredNode's Node Group

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 2.8.0, 3.0.0-alpha1
    • Component/s: None
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      Passing Favored nodes intention is to place replica among the favored node

      Current behavior in Node group is
      If favored node is not available it goes to one among favored nodegroup.

      Say for example:
      	1)I need 3 replicas and passed 5 favored nodes.
      	2)Out of 5 favored nodes 3 favored nodes are not good.
      	3)Then based on BlockPlacementPolicyWithNodeGroup out of 5 targets node returned , 3 will be random node from 3 bad FavoredNode's nodegroup. 
      	4)Then there is a probability that all my 3 replicas are placed on Random node from FavoredNodes's nodegroup , instead of giving priority to 2 favored nodes returned as target.
      

      Instead of returning 5 targets on 3rd step above , we can return 2 good favored nodes as target
      And remaining 1 needed replica can be chosen from Random node of bad FavoredNodes's nodegroup.
      This will make sure that the FavoredNodes are given priority.

        Attachments

        1. HDFS-9044.1.patch
          12 kB
          J.Andreina
        2. HDFS-9044.2.patch
          12 kB
          J.Andreina
        3. HDFS-9044.3.patch
          12 kB
          J.Andreina
        4. HDFS-9044.4.patch
          12 kB
          J.Andreina
        5. HDFS-9044.5.patch
          11 kB
          J.Andreina
        6. HDFS-9044.6.patch
          11 kB
          J.Andreina

          Activity

            People

            • Assignee:
              andreina J.Andreina
              Reporter:
              andreina J.Andreina
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              Dates

              • Created:
                Updated:
                Resolved: