title: hadoop: number of reducers remains a constant 4
body: <p>I'm running a hadoop job with <code>mapred.reduce.tasks = 100</code> (just experimenting). The number of maps spawned are 537 as that depends on the input splits. Problem is the number of reducers "Running" in parallel won't go beyond 4. Even after the maps are 100% complete. Is there a way to increase the number of reducers running as the CPU usage is sub optimal and the Reduce is very slow. </p>
  
  <p>I have also set <code>mapred.tasktracker.reduce.tasks.maximum = 100</code>. But this doesn't seem to affect the numbers of reducers running in parallel.</p>