11gR2 RAC BACKUP FAILS WITH "ORA-00245: CONTROL FILE BACKUP OPERATION FAILED"

In 11gR2 onwards, the controlfile backup happens without holding the control file enqueue. For non-RAC database, this doesn't change anything. But, for RAC database, the snapshot controlfile location must be in a shared file system that will be accessible from all the nodes. The snapshot controlfile MUST be accessible by all nodes of a RAC database.

Solution:

The snapshot controlfile MUST be accessible by all nodes of a RAC database, if the snapshot controlfile does not reside in on a shared device this error will raise.
1. Check the snapshot controlfile location:
rman>show all;
2. Configure the snapshot controlfile to a shared disk:
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '<shared_disk>/snapcf_UNSID1.f'; # default

Reference [ID 1268725.1]