Managing Oracle Cluster Registry (OCR)

Oracle Clusterware automatically creates OCR backups every 4 hours and always retains the latest 3 backup copies of the OCR that are 4 hours old, 1 day old, and 1 week old.

Oracle creates automatic OCR backups in CRS_HOME/cdata/cluster_name.

Given below are the common OCR management tasks.

1. Obtaining the OCR information

$ ocrcheck # gives info regarding version, space, ID and file-name(disk)

2. Viewing Available OCR backups

$ ocrconfig –showbackup

3. Backing Up the OCR

$ ocrconfig -export backup_file_name

In addition to using the automatically created OCR backup files, you should also export the OCR contents to a file before and after making significant configuration changes, such as adding or deleting nodes from your environment, modifying Oracle Clusterware resources, or creating a database. Exporting the OCR contents to a file lets you restore the OCR if your configuration changes cause errors.

4. Recovering OCR

a. Check the status of OCR

# ocrconfig –showbackup

b. Restore the OCR from an automatically generated backup

$ ocrdump -backupfile backup_file_name

- review OCR backup file contents (filename obtained from ocrconfig)

# crsctl stop crs

- stop cluterware on ALL NODES

# ocrconfig -restore backup_file_name

- Apply the OCR backup to the appropriate OCR disk

# crsctl start crs

- start Clusterware on ALL NODES

$ cluvfy comp ocr -n all [-verbose]

- verify the OCR integrity for ALL NODES

c. Recovering the OCR from an OCR Export File

# crsctl stop crs

- stop cluterware on ALL NODES

# ocrconfig -import file_name

- import the contents from the OCR export backup taken earlier.

# crsctl start crs

- start Clusterware on ALL NODES

$ cluvfy comp ocr -n all [-verbose]

- verify the OCR integrity for ALL NODES

5. Replacing an OCR

Changing the location of an OCR is possible as long as at least one OCR disk remains accessible to the Clusteware.

# crsctl check crs

- Check the CRS status

# ocrconfig -replace ocr destination_file

# ocrconfig -replace ocr disk

- Replace the old OCR with the new OCR disk/file

# ocrconfig -replace ocrmirror destination_file

# ocrconfig -replace ocrmirror disk

- Replace the old OCR mirror with the new OCR mirror disk/file

# ocrconfig –repair

- Repair the OCR

6. Repairing an Oracle Cluster Registry Configuration on a Local Node

One may face this scenario when an OCR is incorrectly updated on one node. i.e. you might have added/repaired/removed an OCR

disk on one node when the other node was down, and hence it does not know the changes made to the configuration.

# ocrconfig –repair ocrmirror device_name

Ensure the Clusterware daemons are down on the node where you are executing this command.

7. Removing an Oracle Cluster Registry

You figure out the scenario for this. Here ‘s how you do it.

# ocrconfig -replace ocr

OK, start crashing that test system (hopefully on a virtual machine) now.