How to View No. Of Nodes configured in oracle 11g RAC:
The below command can be used to find out the number of nodes registered into the cluster.
It also displays the node's Public name, Private name and Virtual name along with their numbers.
olsnodes -n -p -i
[root@node1-pub ~]# olsnodes -n -p -i
node1-pub 1 node1-prv node1-vip
node2-pub 2 node2-prv node2-vip