title: How to migrate data from Cassandra cluster of size N to a different cluster of size N+/-M
body: <p>I'm trying to figure out how to migrate data from one cassandra cluster, to another cassandra cluster of a different ring size...say from a 5 node cluster to a 7 node cluster.</p>
  
  <p>I started looking at sstable2json, since it creates a json file for the SSTable on that specific cassandra node.  My thought was to do this for a column family on each node in the ring.  So on a 5 node ring, this would give me 5 json files, one file for the data stored on in the column family that resides on each node.  </p>
  
  <p>Then I'd merge the json files into one file, and use json2sstable to import into a new cluster, of size, lets say 7.  I was hoping that cassandra would then replicate/balance the data out evenly across the nodes in the ring, but I just read that SSTables are immutable once written.  So if I did what I just mentioned, I'd end up with a ring with all the data in my column family on one node.</p>
  
  <p>So can anyone help me figure out the process for migrating data from one cluster to a different cluster of a different ring size?</p>