To configure BlackBerry® MDS Connection Service high availability, you can configure a pool of two or more BlackBerry MDS Connection Service instances. Once you configure a BlackBerry MDS Connection Service pool, the BlackBerry® Enterprise Server assigns one of the connections to the BlackBerry MDS Connection Service instances as the active connection, and the others as standby connections. Multiple BlackBerry Enterprise Server instances can use a single BlackBerry MDS Connection Service pool, and assign active connections to different BlackBerry MDS Connection Service instances. You can configure manual or automatic failover.

Each BlackBerry MDS Connection Service instance writes its health information to the BlackBerry Dispatcher. If the BlackBerry MDS Connection Service cannot connect to the BlackBerry Dispatcher, the BlackBerry Dispatcher lowers the health score of the BlackBerry MDS Connection Service to zero and fails over.

The BlackBerry MDS Connection Service collects health information, such as the status of its last known connection, from the BlackBerry MDS Integration Service. The BlackBerry MDS Connection Service passes this information to the BlackBerry Dispatcher.

If multiple BlackBerry MDS Connection Service instances exist, the BlackBerry Dispatcher uses the health score of the instances to determine which BlackBerry MDS Connection Service it assigns the active connection to.

• High availability for the BlackBerry MDS Connection Service central push server
  
• BlackBerry MDS Connection Service high availability in a small-scale environment
  
• BlackBerry MDS Connection Service high availability in a large-scale environment
  
• Best practice: Planning for BlackBerry MDS Connection Service high availability
  
• Scenario: What happens after the BlackBerry MDS Connection Service stops responding
  
• Scenario: What happens after the BlackBerry MDS Connection Service central push server stops responding
  
• Scenario: What happens after the primary BlackBerry Dispatcher promotes a connection to a BlackBerry MDS Connection Service