Beginning with 188.8.131.52, for any form of database control file backup operations, Oracle no longer acquires the
controlfile enqueue lock.
This change requires snapshot control file accessibility to all instances in a RAC database, in contrast to a single-instance database, to successfully complete a manual or auto control file backup operation.
When the snapshot control file is not accessible or doesn’t exist across instances, the backup of control file operations, including RMAN backups, will fail with an ‘ORA-00245: control file backup operation failed’ error.
To prevent an ORA-00245 error, the snapshot control file must be placed on a shared location or on ASM
DISKGROUP, ensuring that each instance of RAC database has the read and write ability on the file.
To display snapshot control file configuration details, connect to an RMAN prompt and execute one of the
RMAN> show snapshot controlfile name;