title: Is Solr stable enough to use as main repository?
body: <p>I'm testing Solr as my full text search engine provider over 1,000,000 documents.
  I have also users information data which is related to the documents as creator and I want to store the users hit. </p>
  
  <p>Is it necessary to have database engine to store all the data? Or Solr is stable and safe to rely on?
  Is there any risk to loose the stored data in Solr (I know it can happen to Solr index and I can rebuild it, but how about RAW data?)</p>
  
  <p>The only reason that I want to have 2nd storage is having another backup/version of all of my data (not for querying,...).</p>