In Data Center Security Server Advance 6.0
If you navigate to the below location
DCS console - > Admin - > Settings - View configuration - > Master Server : 'Server Name and IP address'
When you have 2 or more DCS server installed and using same SQL DB, you will see the same name on all the DCS console.
This is actually not referring to the Primary DCS server.
It refers to which DCS server is resposible to send an alerts.
To determine, if you have got 2 DCS server , turn off your actualy primary DCS server, then you will see the 'Master server' name shows your secondary DCS server name.