DSE Advanced Replication keyspace overview 

Information about DSE Advanced Replication keyspaces and tables.

Keyspaces and tables are automatically created on the edge cluster when DSE Advanced Replication runs for the first time. Two keyspaces are used, dse_system and dse_advrep. Each keyspace is configured differently.
Note: System keyspace on the edge and hub nodes are not supported for advanced replication.
The dse_system keyspace uses the EverywhereStrategy replication strategy by default; this setting must not be altered. The dse_advrep keyspace is configured to use the SimpleStrategy replication strategy by default and this setting must be updated in production environments to avoid data loss. After starting the cluster, alter the keyspace to use the NetworkTopologyStrategy replication strategy with an appropriate settings for the replication factor and datacenters. For example, use a CQL statement to configure a replication factor of 3 on the DC1 datacenter using NetworkTopologyStrategy:
ALTER KEYSPACE dse_advrep
WITH REPLICATION = {
   'class': 'NetworkTopologyStrategy', 
   'DC1': '3'};
For most environments using DSE Advanced Replication, a replication factor of 3 is suitable. The strategy must be configured for any datacenters which are serving as an advanced replication edge.
nodetool repair must be run on each node of the affected datacenters. to repair the altered keyspace:
nodetool repair -full dse_advrep

For more information, see Changing keyspace replication strategy.