What OCR does and OCR commands

Working with OCR :- check cat /etc/oracle/ocr.loc
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OCR Maintains
Nodeslist in the Cluster
Node membership mapping
Database Instance, node and other mapping information
Applications information controlled by CRS.
CRSD backups the OCR for every 4 hours and retains last 3 backups.
It can be mirrored and Backed up.

1. ocrcheck   # to see the current location
2. ocrdump    # to see the contents of OCR
3. ocrconfig -export /tmp/ocr-export.dmp # Backup OCR
4. ocrconfig -restore <file> # Restore OCR from failure
5. ocrconfig -showbackup
6. ocrconfig -backuploc <path|+ASM>
7. ocrconfig -manualbackup
8. ocrconfig -delete <file>
9. ocrconfig -replace ocrmirror '/acfs2loc/ocr2.dbf'
10. ocrconfig -replace ocr '/acfs2loc/ocr2.dbf'
11. ocrconfig -replace ocr
12. ocrconfig -replace ocrmirror /ocr/ocrdisk2  # to add mirror first touch /ocr/ocrdisk2
13. root]ls G_H/crs_1/cdata/crs/  # Check OCR Backup Physically
14. ocrcheck -local     # Check OLR Location
15. ocrconfig -local -export /home/oracle/olr.backup # Logical BKP of OLR
16. ocrconfig -showbackup -manual.
17. ocrconfig -add +FRA
18. ocrconfig -delete +FRA

Simulate a Failure:-
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1. root] ocrconfig -showbackup
2. root] crsctl stop crs
3. root] mv /ocr/ocrdisk1 /ocr/ocrdisk1_bkp
4. root] crsctl start crs   # will not be started.
5. root] crs_stat -t
6. root] crsctl check boot   # Restoring OCR from auto backup
7. root] ocrconfig -showbackup
8. root] ocrconfig -restore /u01/ocrbkp.ocr
9. root] touch /ocr/ocrdisk1 /ocr/ocrdisk2
10.root] ocrconfig -restore /u01/ocrbkp.ocr
11.root] ocrconfig -import /tmp/ocr-export.dmp

Cluster commands to check votedisk:-
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1. crsctl query css votedisk
2. crsctl add css votedisk <file>
3. crsctl delete css votedisk <file>

CSSD Monitor Process checks health and the heartbeat of N/W and Disk heart beat.