Is my database a RAC database?

To check whether a database is a RAC database from SQL Plus

show parameter cluster

 

To check the details of the  instances from SQL Plus run the following command

SQL> select * from v$active_instances;

INST_NUMBER
———–
INST_NAME
——————————————————————————————————————————————————————————————————–
          1
testdadb01.net:wqa1

          2
testdadb02.net:wqa2

 

Or use srvctl  command to check the database instance details.

oracle:wqa1:/home/oracle$ srvctl status database -d edwqa -v
Instance wqa1 is running on node testdadb01. Instance status: Open.
Instance wqa2 is running on node testdadb02. Instance status: Open.