title: Authentication failures in cassandra when 1 of 16 nodes is down
body: <p>I have a Cassandra cluster running :</p>
  
  <p><em>Cassandra 2.0.11.83 | DSE 4.6.0 | CQL spec 3.1.1 | Thrift protocol 19.39.0</em></p>
  
  <p>The cluster has 18 nodes, split among 3 datacenters, 6 in each. My system_auth keyspace has the following replication defined:</p>
  
  <p><em>replication = {
    'class': 'NetworkTopologyStrategy',
    'DC1': '4',
    'DC2': '4',
    'DC3': '4'}</em></p>
  
  <p>and my authenticator/authorizer are set to:</p>
  
  <p><em>authenticator: org.apache.cassandra.auth.PasswordAuthenticator</em></p>
  
  <p><em>authorizer: org.apache.cassandra.auth.CassandraAuthorizer</em></p>
  
  <p>This morning I brought down one of the nodes in DC1 for maintenance. Within a few seconds/minute client applications started logging exceptions like this:</p>
  
  <p><em>"User my_application_user has no MODIFY permission on  or any of its parents"</em></p>
  
  <p>Running 'LIST ALL PERMISSIONS of my_application_user' on one of the other nodes shows that user to have SELECT and MODIFY on the keyspace xxxxx, so I am rather confused. Do I have a setup issue? Is this a bug of some sort?</p>