The Oracle Cluster Registry (OCR) is one of the most important components for a cluster to ensure smooth operation. Regular backup of the OCR is therefore essential. Up to and including version 12c Release 1, the OCR Master created a backup every four hours and saved it under $ORACLE_HOME/cdata .
As of Oracle 12c Release 2, OCR backups are stored in an ASM disk group - by default, the first ASM disk group created is used. The advantage of this storage is that all cluster nodes have access to the OCR backups.
But what happens if the belarus telegram screening ASM disk group can no longer be mounted, for example because there are problems starting the Oracle stack or the associated LUNs are no longer available? Depending on the situation, only the ASM Metadata Dump Utility ( amdu ) can help at this point to extract files from an unmounted disk group.
The use of amdu is not trivial and should be avoided if possible. Using a file system location will prevent Oracle from doing so with an error message.
PROT-42: The specified backup location '/ocr' is not an ASM disk group.
To protect yourself from such problems, the OCR backup should be regularly copied out of ASM and copied to an external backup server.