Migrating Oracle Cluster Registry to Oracle Automatic Storage Management

To improve Oracle Clusterware storage manageability, OCR is configured, by default, to use Oracle ASM in Oracle Database 12c. With the Oracle Clusterware storage residing in an Oracle ASM disk group, you can manage both database and clusterware storage using Oracle Enterprise Manager.

However, if you upgrade from a previous version of Oracle Clusterware, you can migrate OCR to reside on Oracle ASM, and take advantage of the improvements in managing Oracle Clusterware storage.

Note:

If you upgrade from a previous version of Oracle Clusterware to Oracle Clusterware 12c and you want to store OCR in an Oracle ASM disk group, then you must set the ASM Compatibility compatibility attribute to 11.2.0.2, or later.

See Also:

Oracle Automatic Storage Management Administrator's Guide for information about setting Oracle ASM compatibility attributes

To migrate OCR to Oracle ASM using OCRCONFIG:

Ensure the upgrade to Oracle Clusterware 12c is complete. Run the following command to verify the current running version:
```
$ crsctl query crs activeversion
```
Use the Oracle ASM Configuration Assistant (ASMCA) to configure and start Oracle ASM on all nodes in the cluster.

See Also:

Oracle Automatic Storage Management Administrator's Guide for more information about using ASMCA
Use ASMCA to create an Oracle ASM disk group that is at least the same size of the existing OCR and has at least normal redundancy.
Note:
- If OCR is stored in an Oracle ASM disk group with external redundancy, then Oracle recommends that you add another OCR ___location to another disk group to avoid the loss of OCR, if a disk fails in the disk group.
  
  Oracle does not support storing OCR on different storage types simultaneously, such as storing OCR on both Oracle ASM and a shared file system, except during a migration.
- If an Oracle ASM instance fails on any node, then OCR becomes unavailable on that particular node.
  
  If the CRSD process running on the node affected by the Oracle ASM instance failure is the OCR writer, the majority of the OCR locations are stored in Oracle ASM, and you attempt I/O on OCR during the time the Oracle ASM instance is down on this node, then CRSD stops and becomes inoperable. Cluster management is now affected on this particular node.
  
  Under no circumstances will the failure of one Oracle ASM instance on one node affect the whole cluster.
- Ensure that Oracle ASM disk groups that you create are mounted on all of the nodes in the cluster.
See Also:

Oracle Grid Infrastructure Installation Guide for more detailed sizing information
To add OCR to an Oracle ASM disk group, ensure that the Oracle Clusterware stack is running and run the following command as root:
```
# ocrconfig -add +new_disk_group
```
You can run this command more than once if you add multiple OCR locations. You can have up to five OCR locations. However, each successive run must point to a different disk group.
To remove storage configurations no longer in use, run the following command as root:
```
# ocrconfig -delete old_storage_location
```
Run this command for every configured OCR.

The following example shows how to migrate two OCRs to Oracle ASM using OCRCONFIG.

# ocrconfig -add +new_disk_group
# ocrconfig -delete /ocrdata/ocr_1
# ocrconfig -delete /ocrdata/ocr_2

Note:

OCR inherits the redundancy of the disk group. If you want high redundancy for OCR, you must configure the disk group with high redundancy when you create it.
Oracle recommends that you put the SPFILE for Oracle ASM in this newly-created OCR ___location.