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  1. Hadoop Common
  2. HADOOP-1652

Rebalance data blocks when new data nodes added or data nodes become full



    • Type: New Feature
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 0.13.0
    • Fix Version/s: 0.16.0
    • Component/s: None
    • Labels:


      When a new data node joins hdfs cluster, it does not hold much data. So any map task assigned to the machine most likely does not read local data, thus increasing the use of network bandwidth. On the other hand, when some data nodes become full, new data blocks are placed on only non-full data nodes, thus reducing their read parallelism.

      This jira aims to find an approach to redistribute data blocks when imbalance occurs in the cluster. An solution should meet the following requirements:
      1. It maintains data availablility guranteens in the sense that rebalancing does not reduce the number of replicas that a block has or the number of racks that the block resides.
      2. An adminstrator should be able to invoke and interrupt rebalancing from a command line.
      3. Rebalancing should be throttled so that rebalancing does not cause a namenode to be too busy to serve any incoming request or saturate the network.


        1. Balancer.html
          20 kB
          Ravi Phulari
        2. balancer.patch
          51 kB
          Hairong Kuang
        3. balancer1.patch
          65 kB
          Hairong Kuang
        4. balancer2.patch
          71 kB
          Hairong Kuang
        5. balancer3.patch
          75 kB
          Hairong Kuang
        6. balancer4.patch
          71 kB
          Hairong Kuang
        7. balancer5.patch
          71 kB
          Hairong Kuang
        8. balancer6.patch
          71 kB
          Hairong Kuang
        9. balancer7.patch
          72 kB
          Hairong Kuang
        10. balancer8.patch
          72 kB
          Hairong Kuang
        11. BalancerAdminGuide.pdf
          13 kB
          Hairong Kuang
        12. BalancerAdminGuide1.pdf
          14 kB
          Hairong Kuang
        13. BalancerUserGuide2.pdf
          14 kB
          Hairong Kuang
        14. RebalanceDesign4.pdf
          47 kB
          Hairong Kuang
        15. RebalanceDesign5.pdf
          45 kB
          Hairong Kuang
        16. RebalanceDesign6.pdf
          50 kB
          Hairong Kuang

          Issue Links



              • Assignee:
                hairong Hairong Kuang
                hairong Hairong Kuang
              • Votes:
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                • Created: