00245, 00000, "control file backup operation failed"
// *Cause: Failed to create a control file backup because some process
// signaled an error during backup creation.
// *Action: Check alert files for further information. This usually happens
// because some process could not access the backup file during
// backup creation. Any process of any instance that starts a read/write
// control file transaction must have an access to the backup control file
// during backup creation.
Oracle is too dumb to lie.
Believe the error message
Is this a RAC database?
1. Check the snapshot controlfile location:
RMAN> show all;
2. Configure the snapshot controlfile to a shared disk:
RMAN> CONFIGURE SNAPSHOT CONTROLFILE NAME TO '<shared_disk>/snapcf_<DBNAME>.f';
3. connect to RMAN and issue:
RMAN> CONFIGURE SNAPSHOT CONTROLFILE NAME TO <shared_location_file>;
This location must be available to EACH node.
4. A controlfile copy created by either Sqlplus or RMAN backup must also reside on a shared device. I.e.,:
SQL> alter database backup controlfile to '/........./control_backup.ctl' reuse;
RMAN> copy current controlfile to '/......./control_backup.bak';
will fail with same "ORA-00245: control file backup operation failed" error if the location to create the controlfile backup is NOT a shared device.
Due to the changes made to the controlfile backup mechanism any instances in the cluster may write to the backup controlfile when making changes to the current controlfile. Therefore, the backup file needs to be visible to all instances.