Regardless, if you are not modifying users frequently (with five you most likely are not), make sure turn the permission cache waaaayyy up.
In 2.1 that is just: permissions_validity_in_ms (default is 2000 or 2 seconds). Feel free to set it to 1 day or some such. The corresponding async update parameter (permissions_update_interval_in_ms) can be set to a slightly smaller value. If you really need to, you can drop the cache via the "invalidate" operation on the "org.apache.cassandra.auth:type=PermissionsCache" mbean (on each node) to revoke a user for example. In later versions, you would have to do the same with: - roles_validity_in_ms - credentials_validity_in_ms and their corresponding 'interval' parameters.
