title: hadoop storage directory uses space more than total data on HDFS
body: <p>i have a three node hadoop cluster with <strong>replication factor</strong> = 3. </p>
  
  <p><strong>Storage Directory</strong> is <strong>/app/hadoop/tmp/dfs/</strong> for each system.</p>
  
  <p>Each <strong>datanode system</strong> has hard-disk capacity of 221GB. </p>
  
  <p>the <strong>Effective data</strong> of HDFS is 62GB with <strong>replication</strong> 62*3= 186GB. </p>
  
  <p>Now the problem is i am falling short of storage even though i have only 186GB of data on 660 GB cluster:
  HDFS  shows huge difference in the space available for use:</p>
  
  <p>datanode1 =7.47 GB</p>
  
  <p>datanode2 =17.7 GB</p>
  
  <p>datanode3 =143 GB</p>
  
  <p>to make sure that these space is used by hadoop local storage, i ran this command on each datanode.
  for datanode1</p>
  
  <pre><code>du -h --max-depth=1 /app/hadoop/tmp/
  63G     /app/hadoop/tmp/dfs
  139G    /app/hadoop/tmp/mapred
  201G    /app/hadoop/tmp/
  </code></pre>
  
  <p>for datanode2</p>
  
  <pre><code>du -h --max-depth=1 /app/hadoop/tmp/
  126G    /app/hadoop/tmp/mapred
  62G     /app/hadoop/tmp/dfs
  188G    /app/hadoop/tmp/
  </code></pre>
  
  <p>for datanode3
         du -h --max-depth=1 /app/hadoop/tmp/dfs/
      62G     /app/hadoop/tmp/dfs/data
      62G     /app/hadoop/tmp/dfs/</p>
  
  <p><strong>here datanode1 has used 201GB space for storage.</strong>
  I tried load-balancer but its showing the cluster is balanced.
  here is the output.</p>
  
  <pre><code>start-balancer.sh
  starting balancer, logging to /usr/lib/hadoop-0.20/logs/hadoop-ocpe-balancer-blrkec241933d.out
  Time Stamp               Iteration#  Bytes Already Moved  Bytes Left To Move  Bytes Being Moved
  The cluster is balanced. Exiting...
  Balancing took 622.0 milliseconds
  </code></pre>
  
  <p>recently one of my datanode went down for few days, after fixing it this problem has arisen.
  How to balance the load?</p>