Overriding the Oracle Cluster Registry Data Loss Protection Mechanism

OCR has a mechanism that prevents data loss due to accidental overwrites. If you configure a mirrored OCR and if Oracle Clusterware cannot access the mirrored OCR locations and also cannot verify that the available OCR ___location contains the most recent configuration, then Oracle Clusterware prevents further modification to the available OCR ___location. In addition, the process prevents overwriting by prohibiting Oracle Clusterware from starting on the node on which only one OCR is available. In such cases, Oracle Database displays an alert message in either Oracle Enterprise Manager, the Oracle Clusterware alert log files, or both. If this problem is local to only one node, you can use other nodes to start your cluster database.

However, if you are unable to start any cluster node in your environment and if you can neither repair OCR nor restore access to all OCR locations, then you can override the protection mechanism. The procedure described in the following list enables you to start the cluster using the available OCR ___location. However, overriding the protection mechanism can result in the loss of data that was not available when the previous known good state was created.

Caution:

Overriding OCR using the following procedure can result in the loss of OCR updates that were made between the time of the last known good OCR update made to the currently accessible OCR and the time at which you performed the overwrite. In other words, running the ocrconfig -overwrite command can result in data loss if the OCR ___location that you are using to perform the overwrite does not contain the latest configuration updates for your cluster environment.

Perform the following procedure to overwrite OCR if a node cannot start and if the alert log contains CLSD-1009 and CLSD-1011 messages.

  1. Attempt to resolve the cause of the CLSD-1009 and CLSD-1011 messages.

    Compare the node's OCR configuration (ocr.loc on Linux and UNIX systems and the Registry on Windows systems) with other nodes on which Oracle Clusterware is running.

    • If the configurations do not match, run ocrconfig -repair.

    • If the configurations match, ensure that the node can access all of the configured OCRs by running an ls command on Linux and UNIX systems. On Windows, use a dir command if the OCR ___location is a file and run GuiOracleObjectManager.exe to verify that the part of the cluster with the name exists.

  2. Ensure that the most recent OCR contains the latest OCR updates.

    Look at output from the ocrdump command and determine whether it has your latest updates.

  3. If you cannot resolve the problem that caused the CLSD message, then run the command ocrconfig -overwrite to start the node.