Solution:
This happens when you havea RAC setup and you are backing up the Snapshot of the controlfile to a local disk instead of a shared disk.
In our setup we setup an ACFS file system on both nodes of RAC and changed RMAN parameter as below
RMAN> CONFIGURE SNAPSHOT CONTROLFILE NAME TO ‘/ACFS/snapcf_mw1.f’;
new RMAN configuration parameters:
CONFIGURE SNAPSHOT CONTROLFILE NAME TO ‘/ACFS/snapcf_mw1.f’;
new RMAN configuration parameters are successfully stored