The Master Node determination in oracle RAC

The CRSD process only creates automatic OCR physical backups on one node in the cluster, which is the OCR master node. It does not create automatic backup copies on the other nodes; only from the OCR master node. If the master node fails, the OCR backups will be created from the new master node. You can determine which node in the cluster is the master node by examining the $ORA_CRS_HOME/log//cssd/ocssd.log file on any node in the cluster. In this log file, check for reconfiguration information (reconfiguration successful) after which you will see which node is the master and how many nodes are active in the cluster:

Node 1 - (racnode1)
[ CSSD]CLSS-3000: reconfiguration successful, incarnation 1 with 2 nodes
[ CSSD]CLSS-3001: local node number 1, master node number 1
Node 2 - (racnode2)
[ CSSD]CLSS-3000: reconfiguration successful, incarnation 1 with 2 nodes
[ CSSD]CLSS-3001: local node number 2, master node number 1

Another quick approach is to use either of the following methods:

Node 1 - (racnode1)
# grep -i "master node" $ORA_CRS_HOME/log/racnode?/cssd/ocssd.log tail -1
[ CSSD]CLSS-3001: local node number 1, master node number 1
Node 2 - (racnode2)
# grep -i "master node" $ORA_CRS_HOME/log/racnode?/cssd/ocssd.log tail -1
[ CSSD]CLSS-3001: local node number 2, master node number 1
# If not found in the ocssd.log, then look through all
# of the ocssd archives:
Node 1 - (racnode1)
# for x in 'ls -tr $ORA_CRS_HOME/log/racnode?/cssd/ocssd.*'
do grep -i "master node" $x; done tail -1
[ CSSD]CLSS-3001: local node number 1, master node number 1
Node 2 - (racnode2)
# for x in 'ls -tr $ORA_CRS_HOME/log/racnode?/cssd/ocssd.*'
do grep -i "master node" $x; done tail -1
[ CSSD]CLSS-3001: local node number 2, master node number 1
# The master node information is confirmed by the
# ocrconfig -showbackup command:
# ocrconfig -showbackup
racnode1 2009/09/29 13:05:22 /u01/app/crs/cdata/crs
racnode1 2009/09/29 09:05:22 /u01/app/crs/cdata/crs
racnode1 2009/09/29 05:05:22 /u01/app/crs/cdata/crs
racnode1 2009/09/28 05:05:21 /u01/app/crs/cdata/crs
racnode1 2009/09/22 05:05:13 /u01/app/crs/cdata/crs

You can use any backup software to copy the automatically generated physical backup files to a stable backup location:

[root@racnode1 ~]# cp -p -v -f -R /u01/app/crs/cdata /u02/crs_backup/ocrbackup/RACNODE1
'/u01/app/crs/cdata/crs/day_.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE1/cdata/crs/day_.ocr'
'/u01/app/crs/cdata/crs/backup02.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE1/cdata/crs/backup02.ocr'
'/u01/app/crs/cdata/crs/backup01.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE1/cdata/crs/backup01.ocr'
'/u01/app/crs/cdata/crs/week_.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE1/cdata/crs/week_.ocr'
'/u01/app/crs/cdata/crs/day.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE1/cdata/crs/day.ocr'
'/u01/app/crs/cdata/crs/backup00.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE1/cdata/crs/backup00.ocr'
'/u01/app/crs/cdata/crs/week.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE1/cdata/crs/week.ocr'
[root@racnode2 ~]# cp -p -v -f -R /u01/app/crs/cdata /u02/crs_backup/ocrbackup/RACNODE2
'/u01/app/crs/cdata/crs/day_.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE2/cdata/crs/day_.ocr'
'/u01/app/crs/cdata/crs/backup02.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE2/cdata/crs/backup02.ocr'
'/u01/app/crs/cdata/crs/backup01.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE2/cdata/crs/backup01.ocr'
'/u01/app/crs/cdata/crs/week_.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE2/cdata/crs/week_.ocr'
'/u01/app/crs/cdata/crs/day.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE2/cdata/crs/day.ocr'
'/u01/app/crs/cdata/crs/backup00.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE2/cdata/crs/backup00.ocr'
'/u01/app/crs/cdata/crs/week.ocr' -> '/u02/crs_backup/ocrbackup/RACNODE2/cdata/crs/week.ocr'

Manual OCR Exports :

Performing a manual export of the OCR should be done before and after making significant configuration changes to the cluster, such as adding or deleting nodes from your environment, modifying Oracle Clusterware resources, or creating a database. This type of backup is often referred to as a logical backup.

ocrconfig -export
For example:
[root@racnode1 ~]# ocrconfig -export /u02/crs_backup/ocrbackup/RACNODE1/exports/OCRFileBackup.dmp
To restore the OCR from an export/logical backup, use the ocrconfig –import command-
To restore the OCR from an export/logical backup, use the ocrconfig –import command. Note that the CRS stack needs to be shutdown on all nodes in the cluster prior to running the restore operation. In addition, the total space required for the restored OCR location (typically 280MB) has to be pre-allocated. This is especially important when the OCR is located on a clustered file system like OCFS2.
ocrconfig –import

You cannot restore the OCR from a logical backup using the -restore option. The only method to restore the OCR from a logical export is to use the -import option.