title: Reducing elasticsearch's index size
body: <p>I currently have a large amount of log files being analyzed by Logstash, and therefore a consequent amount of space being used in Elasticsearch. 
  However, a lot of this data is useless to me, as everything is not being displayed in Kibana. </p>
  
  <p>So I'm wondering: is there a way to keep the index size minimal and only store matching events?</p>
  
  <p><strong>Edit:</strong> Perhaps I am being unclear on what I would like to achieve. I have several logs that fall under different categories (because they do not serve the same purpose and are not built the same way). I created several filter configuration files that correspond to these different types of logs. </p>
  
  <p>Currently, all the data from all my logs is being stored in Elasticsearch. For example, say I am looking for the text "cat" in one of my logs, the event containing "cat" will be stored, but so will the other 10,000 lines. I want to avoid this and only store this 1 event in Elasticsearch's index.</p>