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  1. Hadoop HDFS
  2. HDFS-3286

When the threshold value for balancer is 0(zero) ,unexpected output is displayed



    • Bug
    • Status: Closed
    • Major
    • Resolution: Fixed
    • 0.23.0
    • 2.0.0-alpha
    • balancer & mover
    • None
    • Incompatible change, Reviewed


      Replication factor =1
      Step 1: Start NN,DN1.write 4 GB of data
      Step 2: Start DN2
      Step 3: issue the balancer command(./hdfs balancer -threshold 0)

      The threshold parameter is a fraction in the range of (0%, 100%) with a default value of 10%
      When the above scenario is executed the Source DN and Target DN is choosen and the number of bytes to be moved from source to target DN is also calculated .

      Then the balancer is exiting with the following message "No block can be moved. Exiting..." which is not expected.

      HOST-xx-xx-xx-xx:/home/Andreina/APril10/install/hadoop/namenode/bin # ./hdfs balancer -threshold 0
      12/04/16 16:22:07 INFO balancer.Balancer: Using a threshold of 0.0
      12/04/16 16:22:07 INFO balancer.Balancer: namenodes = [hdfs://HOST-xx-xx-xx-xx:9000]
      12/04/16 16:22:07 INFO balancer.Balancer: p         = Balancer.Parameters[BalancingPolicy.Node, threshold=0.0]
      Time Stamp               Iteration#  Bytes Already Moved  Bytes Left To Move  Bytes Being Moved
      12/04/16 16:22:10 INFO net.NetworkTopology: Adding a new node: /default-rack/yy.yy.yy.yy:50176
      12/04/16 16:22:10 INFO net.NetworkTopology: Adding a new node: /default-rack/xx.xx.xx.xx:50010
      12/04/16 16:22:10 INFO balancer.Balancer: 1 over-utilized: [Source[xx.xx.xx.xx:50010, utilization=7.212458091389678]]
      12/04/16 16:22:10 INFO balancer.Balancer: 1 underutilized: [BalancerDatanode[yy.yy.yy.yy:50176, utilization=4.650670324367203E-5]]
      12/04/16 16:22:10 INFO balancer.Balancer: Need to move 1.77 GB to make the cluster balanced.
      No block can be moved. Exiting...
      Balancing took 5.142 seconds


        1. HDFS-3286.patch
          5 kB
          Ashish Singhi
        2. HDFS-3286.patch
          4 kB
          Ashish Singhi
        3. HDFS-3286.patch
          8 kB
          Ashish Singhi
        4. HDFS-3286-1.patch
          4 kB
          Ashish Singhi



            ashish singhi Ashish Singhi
            andreina J.Andreina
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