title: Add server with existing data as DataNode to Hadoop
body: <p>I need to build distributed fail proof (as possible) cluster from several servers with existing data.
  I'm new to Hadoop, but as far as I can tell, it more close to satisfy my requirements than other products.
  The problem is that I already some data (quite large files) which I want to be available in Hadoop.
  Is it possible to add server with existing data as DataNode to Hadoop?
  What should I do to make it possible?    </p>