title: What is the best way to migrate data in Cassandra
body: <p>I have a Cassandra cluster of 5 nodes with  <code>writeConsistency: LOCAL_QUORUM</code>. The cluster has TBs of Data. Now I need to migrate the data to a different <code>keyspace</code> in the same cluster. Following is the requirement.</p>
  
  <pre><code>keyspace_1 --&gt; read data --&gt; transform --&gt; insert in keyspace_2.
  </code></pre>
  
  <p>Now we can do that by some multi-instance microservices, where we can read the data from <code>keyspace_1</code>, and then transform it and then insert it in the target keyspace. </p>
  
  <p>But is there a better approach to it. I have found an article <a href="https://stackoverflow.com/questions/6781132/how-to-migrate-data-from-cassandra-cluster-of-size-n-to-a-different-cluster-of-s">How to migrate data from Cassandra cluster of size N to a different cluster of size N+/-M</a>. But here mainly the SSTable is getting transferred without any transformation. But I need a data transformation mechanism in between. Can anyone suggest me a good approach here/ someone did this type of activity earlier?</p>