title: MongoDB + Elasticsearch or only Elasticsearch?
body: <p>We have a new project there for index a large amount of data and for provide real time. I have also complexe search with facets, full text, geospatial...</p>
  
  <p>The first prototype is to index in MongoDB and next, into Elasticsearch, because I had read that Elasticsearch does not apply a checksum on stored files and the index can't be fully trusted. 
  But since last versions (in the version 1.5), there is now a checksum and I'm guessing if we can use Elasticsearch as primary data store ? And what is the benefit to use MongoDB in addition to Elasticsearch ?</p>
  
  <p>I can't find up to date answer about thoses features in Elasticsearch</p>
  
  <p>Thanks a lot</p>