Problems associated with the Improper Configuration of Listeners parameters in RAC environment lead

Checking the Listener parameters configurations in RAC environment.

Checks if the REMOTE_LISTENER and LOCAL_LISTENER initialization parameters are set for the instance.

Command
sql>show parameter remote_listener
it should be scanname:portnum
ex:   testdbscan:1521
 
sql>show parameter local_listener
It should be vip of that instance

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
local_listener                       string      (DESCRIPTION=(ADDRESS_LIST=(AD
                                                 DRESS=(PROTOCOL=TCP)(HOST=192.168.1.20)(PORT=1521))))
 
192.168.1.20-- vip of that node

Risk

Failure to configure the REMOTE_LISTENER and LOCAL_LISTENER database initialization parameters puts the availability of the database at risk since server side load balancing and connection failover will not be enabled.

Recommendation

Server-side load balancing and failover should be configured for all Oracle RAC environments. This can be accomplished by setting the appropriate values for REMOTE_LISTENER and LOCAL_LISTENER database initialization parameters.

The parameter can be set by using the alter system command (alter system set <parameter_name> = <value> scope=both).