Oracle’s SRVCTL: Enable an Instance. Make an Instance Preferred. Check a Service’s Status.
How to use the Oracle Server Control (srvctl) to enable instances, and see configurations and statuses.
Enabling an Instance
# srvctl enable instance -d [unique database name] -i "[instance1],[instance2]"
Enables instances. If repeated, get messages,
PRCC-1011: [db] was already enabled on [server name 1], [server name 2]
PRCR-1002: Resource [resource name] is already enabled
See the Configuration of a Service
# srvctl config service -d [unique service name]
Provides service name and status, server pool, service role, failover type, preferred instances and available instances.
Change Which Instance is Preferred
# srvctl modify service -d [unique database name] -s [service name] -i [available instance] -r
-r is the command that says to move it from available to preferred.