title: How does Trello store data in MongoDB? (Collection per board?)
body: <p>How does Trello store their data (cards) in MongoDB?</p>
  
  <p>I read ( <a href="https://stackoverflow.com/questions/10505431/how-does-trello-show-history-so-quickly">How does Trello show history so quickly?</a> ) that their Actions collection is the largest one. Thus I assume that they do not store all cards in one gigantic collection. </p>
  
  <p>The only other logical solution seems a collection per board or per user. But they have a lot of users and I read ( <a href="http://www.mongodb.org/display/DOCS/Using+a+Large+Number+of+Collections" rel="nofollow noreferrer">http://www.mongodb.org/display/DOCS/Using+a+Large+Number+of+Collections</a> ) that there is a limit on the number of collections and some people advise against using a lot of collections.</p>
  
  <p>I hope someone from Trello team will answear this AND I hope to get some ideas on solving this kind of a problem also from the general community. </p>