Identify Master node in RAC cluster

1. Grep occsd Log file
[oracle @ tadrac1]: /u1/app/../cssd >grep -i “master node” ocssd.log | tail -1
[CSSD]CLSS-3001: local node number 1, master node number 1

2. Grep crsd log file
[oracle @ tadrac1]: /u1/app/../crsd>grep MASTER crsd.log | tail -1

3. Query V$GES_RESOURCE view

4. ocrconfig -showbackup
The node that store OCR backups is the master node.

The role of the master node is basically that this is the node where other “clients”/nodes will contact to get information about node status… ect.

The rule is like this.
-> the first node in a cluster to be up will become the master node. -> and/or the node with the lowest number will become the master node. Information about who is the master can be found in the cssd logfile. Check for reconfiguration information at the end of the reconfiguration.