Noticed these when working against the current 0.7.0 beta2 (#3) build...

When sending a system_add_keyspace request with an invalid keyspace the response to the client is fine...
InvalidRequestException: InvalidRequestException(why='Invalid keyspace name: Test Keyspace 1285729085.78')

However it's not logged in the system.log. Looking through the code it appears that none of the Config errors are logged at any level. It may be handy to log these as a record of attempted changes on the system.

In thrift/CassandraServer system_add_keyspace() the strategy_class string from the KsDef is used to load a class. The ClassNotFoundError is then caught and used to build an InvalidRequestException. If the strategy_class is missing or empty, the error returned to the client is 

InvalidRequestException: InvalidRequestException(why='')