title: Spatial data with mongodb or cassandra
body: <p>I am considering a Proof of concept for handling large volumes of data like > 10 G which requires atleast 200+ writes per second and about 50+ reads per second of spatial related data. This is a growing system as well. Currently I am considering moving this big volume data into a NoSql big table kind of db for performance reasons.</p>
  
  <p>I have considered and taken some closer look at MongoDB and cassandra. As far as my reading goes,</p>
  
  <p>Mongodb:
    - seems to have a writer lock problem 
    - one of the posts in stackoverflow suggested this db if there is no need for multiple servers
    - indexes kept on memory. So the bigger the index growth, the performance is said to deteriorate
    - advantage is Mongodb has direct support for spatial data &amp; indexing along with features like finding nearby locations etc.,
    - I see this post <a href="https://stackoverflow.com/questions/3527956/cassandra-or-mongodb-for-our-location-based-application">Cassandra Or MongoDB For Our Location Based Application</a> suggesting mongodb as the best choice</p>
  
  <p>Cassandra:<br>
    - Seems to be the best of among the related dbs
    - Seems to have great write as well as read performance
    - Does not natively support spatial indexing but this can be extended via geohashing</p>
  
  <p>My heart actually goes out for mongodb because of its good documentation and direct support for spatial data. Has any body had bad experience using mongodb for such big systems? I actually see lot of posts on mongodb iostat for performance.</p>
  
  <p>If mongodb is not suited, can someone give some pointers on geohashing using cassandra? I saw the link <a href="http://code.google.com/p/geospatialweb/" rel="noreferrer">http://code.google.com/p/geospatialweb/</a> for creating the hashes. But there are questions on how to query etc.?</p>