How to find out the master node ?

How to find out the nodes in RAC cluster (or) 
How to find out the master node in Oracle RAC?

There are several ways to find out which is the master node or all the nodes which are part of Oracle RAC cluster.

Use any one of the below.

i) oclumon manage -get master        (in Oracle RAC 12c)


ii) select MASTER_NODE from v$ges_resource;

iii) ocrconfig -manualbackup


iv) check ocssd.log file and search for "master node number".

$ grep "master node number" /u01/app/crs/11.2.0.4/log/`hostname -s`/cssd/ocssd.log




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ocrconfig commands in Oracle RAC

Oracle RAC ocrconfig commands

OCRCONFIG: -- OCR (Oracle Cluster Registry) CONFIGuration tool / Oracle Local Registry (OLR) config tool

#ocrconfig -help or ocrconfig -h

ocrconfig [option]
option:
[-local] -export filename - Export OCR/OLR contents to a file
[-local] -import filename        - Import OCR/OLR contents from a file
[-local] -upgrade [user [group]] - Upgrade OCR from previous version
-downgrade [-version version string] - Downgrade OCR to the specified version
[-local] -backuploc [dirname | +diskgroupname ]        - Configure OCR/OLR backup location
[-local] -showbackup [auto|manual]  - Show OCR/OLR backup information
[-local] -manualbackup              - Perform OCR/OLR backup
[-local] -restore filename        - Restore OCR/OLR from physical backup
-replace current filename -replacement new filename - Replace an OCR device or file current filename with new filename
-add filename                      - Add a new OCR device/file
-delete filename                  - Remove a OCR device/file
-overwrite                          - Overwrite OCR configuration on disk
-repair -add filename | -delete filename | -replace current filename -replacement new filename - Repair OCR configuration on the local node
-help                                - Print out this help information

In Oracle 12c RAC,
[-local] -showbackuploc              - Show OCR/OLR backup location
-copy source_filename destination_filename  - Copy OCR physical backup from source to destination

# ocrconfig -showbackup [auto|manual]   -- default location is $ORA_CRS_HOME/cdata/cluster_name

# ocrconfig -showbackup
# ocrconfig -backuploc dir_name    -- change OCR autobackup directory location
# ocrconfig -backuploc /u02/backups

# ocrconfig -manualbackup      -- Oracle RAC 11g command, to perform OCR backup manually
# ocrconfig -restore backup_file.ocr    -- recovering from autobackup file
# ocrconfig -restore /u02/backups/backup00.ocr
# ocrconfig -restore /u01/app/11.2.0/gi/cdata/cluster-name/backup02.ocr

# ocrconfig -export file_name.dmp [-s online]     -- exports OCR content to a file

# ocrconfig -export /tmp/ocr_exp
# ocrconfig -import file_name.dmp      -- recover OCR logically, must be done on all nodes

# ocrconfig -import /tmp/ocr_exp

# ocrconfig -replace ocr [file_name]   -- adding/replacing an OCR file

# ocrconfig -replace ocrmirror [file_name]

# ocrconfig -replace ocrmirror /data/ocr/ocrfile2

# ocrconfig -repair ocr file_name

# ocrconfig -repair ocrmirror file_name

# ocrconfig -repair -replace current_OCR_location -replacement target_OCR_location

# ocrconfig -upgrade [user [group]]         -- upgrades OCR

# ocrconfig -downgrade [-version version_string]   -- downgrades OCR

# ocrconfig -overwrite

# ocrconfig –local –import file_name

# ocrconfig –local –manualbackup

# ocrconfig -local -backuploc new_olr_backup_path

# ocrconfig -local -restore file_name

# ocrconfig -local -restore $GRID_HOME/cdata/host06/backup_20171106_02946.olr   --restoring OLR file

# ocrconfig -add +new_disk_group

# ocrconfig -add file_location

# ocrconfig -add /dev/sdd1

# ocrconfig -delete +unused_disk_group

# ocrconfig -delete old_storage_location

# ocrconfig -delete /dev/raw/raw2

Log file will be $ORACLE_HOME/log/node_name/client/ocrconfig_pid.log

Debugging can be controlled through $ORA_CRS_HOME/srvm/admin/ocrlog.ini

How to take backup of OCR / OLR file?

# ocrconfig -manualbackup

# ocrconfig -export file_name.dmp

How to recover OCR / OLR file?

# ocrconfig -restore backup_file.ocr

# ocrconfig -import file_name.dmp

Related Oracle RAC Articles:     ocrdump commands RAC     ocrcheck commands RAC