Remove the User Cassandra from DataStax\Apache Cassandra Installations
Whenever you’re installing a new DataStax\Apache Cassandra cluster, you need to remember to remove the user cassandra.
We’ve seen this at a couple of customer installations now. If you do not change the user cassandra or at least alter the roles for the user cassandra. then you’re liable to see all sort of nasty repercussions. The cassandra user uses a consistency level of QUORUM when querying keyspaces like ‘system_auth’. Hence, you may see significant performance degradation because each query will need to have confirmation.
In your Cassandra system log files, you’ll most likely see