Master and Slave Name Servers 

The name servers in a distributed system have one of the following roles:

·        Master name servers

·        Slave name server

The master name servers can update the topology data for the system. The slave name servers can only read the topology data.

In a distributed system you need at least two master name servers, and cannot define more than three. The system automatically defines an active master. If the active master is unavailable, the next master name server takes over the tasks.