Servers and services
When the main network is running properly, the disaster recovery servers are powered on, but their services are stopped. This configuration allows for server maintenance such as security patches. Because the services are off, TCP connections are quickly rejected if there is an attempt to connect to one of the disaster recovery servers.
In a disaster recovery event, the primary servers go offline. An administrator must manually start the services on the disaster recovery servers after the failover of the databases is complete.
The high availability configuration for all clusters is at least n + 1 (the number of servers you require plus one or more servers for high availability).