title: Namenode stops working after hadoop restart
body: <p>I have a server with Hadoop installed on.</p>
  
  <p>I wanted to change some configuration (about the <code>mapreduce.map.output.compress</code>); therefore, I changed the configuration file, and I restarted Hadoop, with:</p>
  
  <pre><code>stop-all.sh
  start-all.sh
  </code></pre>
  
  <p>After that, I was not able to use it again, becouse it was in Safe Mode:</p>
  
  <p><code>The reported blocks is only 0 but the threshold is 0.9990 and the total blocks 11313. Safe mode will be turned off automatically</code>.</p>
  
  <p>Please, notice that the number of reported blocks is 0, and it was not increasing at all.</p>
  
  <p>Therefore, I forced it to leave the Safe Mode with:</p>
  
  <pre><code>bin/hadoop dfsadmin -safemode leave
  </code></pre>
  
  <p>Now, I get errors like this:</p>
  
  <pre><code>2014-03-09 18:16:40,586 [Thread-1] ERROR org.apache.hadoop.hdfs.DFSClient - Failed to close file /tmp/temp-39739076/tmp2073328134/GQL.jar
  org.apache.hadoop.ipc.RemoteException: java.io.IOException: File /tmp/temp-39739076/tmp2073328134/GQL.jar could only be replicated to 0 nodes, instead of 1
  </code></pre>
  
  <p>If it helps, my <code>hdfs-site.xml</code> is:</p>
  
  <pre><code>&lt;configuration&gt;
  &lt;property&gt;
          &lt;name&gt;dfs.replication&lt;/name&gt;
          &lt;value&gt;1&lt;/value&gt;
  &lt;/property&gt;
  &lt;property&gt;
      &lt;name&gt;dfs.name.dir&lt;/name&gt;
      &lt;value&gt;/home/hduser/hadoop/name/data&lt;/value&gt;
  &lt;/property&gt;
  
  
  &lt;/configuration&gt;
  </code></pre>