Cassandra:nodetool usage

Nodetool is a OOTB tool from Cassandra.  It provides various options to manage the keyspace.  There were three useful options I came across:

1) I had to copy the keyspace from one server to another server.  Since the source is from multiple servers, it is essential to cleanup the data after all the db and its related files are copied.  For that, I have to use nodetool.  Nodetool usually resides in <cassandra-path>/bin.  To cleanup, give the following command:

            nodetool -h <hostname of the cassandra> cleanup

Based on the amount of data to be cleaned, it will take some time.To track the progress, you can use:

            nodetool compactionstats

This will print the following:

pending tasks: 1
          compaction type        keyspace   column family       completed           total      unit  progress
                  Cleanup             <keyspace-name>      <column-family-name>      1667500496      2004577146     bytes    83.18%

Note: the total column will vary based on the size that is being calculated in real time.

2) To get the statistics of all the keyspaces. Especially to get a rough idea of how much keys per column family are being used:

           nodetool -h <hostname> cfstats