title: Modify mapper size (split size) in MapReduce to have a faster performance
body: <p>Are there any ways to improve the MapReduce performance by changing the number of map tasks or changing the split sizes of each mapper?
  For example, I have a 100GB text file and 20 nodes. I want to run a WordCount job on the text file, what is the ideal number of mappers or the ideal split size so that it can be done faster?</p>
  
  <p>Would it be faster with more mappers?
  Would it be faster with a smaller split size?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>I am using hadoop 2.7.1, just so you know there is YARN.</p>