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      Name Space Quotas Administrator Guide
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<h1>
      Name Space Quotas Administrator Guide
    </h1>
      
<p>
      The Hadoop Distributed File System (HDFS) allows the administrator to set quotas on individual directories. 
      Newly created directories have no associated quota. 
      The largest quota is <span class="codefrag">Long.Max_Value</span>. A quota of one forces a directory 
      to remain empty.
      </p>

      
<p>
      The directory quota is a hard limit on the number of names in the tree 
      rooted at that directory. File and directory creations fault if the quota 
      would be exceeded. Quotas stick to renamed directories; the rename 
      operation faults if operation would result in a quota violation. 
      The attempt to set a quota faults if the directory would be in violation 
      of the new quota.
      </p>

      
<p>
      Quotas are persistent with the fsimage. When starting, if the fsimage 
      is immediately in violation of a quota (perhaps the fsimage was 
      surreptitiously modified), the startup operation fails with an error report. 
      Setting or removing a quota creates a journal entry.
      </p> 

      
<p>
      The following new commands or new options are added to support quotas. 
      The first two are administration commands.
      </p>

      
<ul>
      
<li>
      
<span class="codefrag">dfsadmin -setquota &lt;N&gt; &lt;directory&gt;...&lt;directory&gt;</span> 
      
<br>
      Set the quota to be <span class="codefrag">N</span> for each directory. Best effort for each directory,
      with faults reported if <span class="codefrag">N</span> is not a positive long integer, 
      the directory does not exist or it is a file, or the directory would 
      immediately exceed the new quota.
      </li>
  
      
<li>
      
<span class="codefrag">dfsadmin -clrquota &lt;directory&gt;...&lt;director&gt;</span>
<br> 
      Remove any quota for each directory. Best effort for each directory, 
      with faults reported if the directory does not exist or it is a file. 
      It is not a fault if the directory has no quota.
      </li>
  
      
<li>
      
<span class="codefrag">fs -count -q &lt;directory&gt;...&lt;directory&gt;</span>
<br>
      With the <span class="codefrag">-q</span> option, also report the quota value set for each 
      directory, and the available quota remaining. If the directory does not have 
      a quota set, the reported values are <span class="codefrag">none</span> and <span class="codefrag">inf</span>.
      </li>
      
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