Connection failover provides failover protection for new connections only. The data provider fails over new connections to an alternate, or backup, database server if the primary database is unavailable, for example, because of a hardware failure or traffic overload. Alternate servers are tried until a connection is successfully established or until all database servers (primary and alternate) have been tried a specified number of times. If a connection to the database is lost, or dropped, the data provider does not fail over the connection.
For example, as shown in Figure 3-1, Database Server A is designated as the primary database server, Database Server B is the first alternate server, and Database Server C is the second alternate server.
First, the data provider attempts to connect to the primary database, Database Server A (1). If connection failover is enabled and Database Server A fails to accept the connection, the data provider attempts to connect to Database Server B (
2). If that connection attempt also fails, the data provider attempts to connect to Database Server C (
3).