title: Saving output of completed mappers in map only architecture even if some mappers fail
body: <p>I am running map only (number of reducers = 0) map reduce streaming job. At the end of the mapper code, I write the output of map explicitly. However at times some of my mapper tasks fails.</p>
  
  <p>I was expecting to see the output of completed mappers in HDFS. My logic was as there is no reducer so output should be directly written to HDFS. However I couldn't see any data in output HDFS folder in case even a single mapper fails. Why this happens? Is there any flaw in my understanding?</p>