ORA-00245: control file backup failed; target is likely on a local file system

Cause: From 11gR2 onwards, the controlfile backup happens without holding the controlfile enqueue. For non-RAC database, this doesn't change anything. But for RAC database, due to the changes made to the controlfile backup mechanism in 11gR2, any instance in the cluster may write to the snapshot controlfile. Due to this snapshot controlfile need to be visible to all instances. 

Solution: The snapshot controlfile MUST be accessible by all nodes of a RAC database, if the snapshot controlfile does not reside on a shared device error will be raised at the time of RMAN backup while taking snapshot of controlfile. So placed controlfile into the Shared Disk.

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================

RMAN-03009: failure of backup command on CH3 channel at 04/05/2017 01:54:55
ORA-00245: control file backup failed; target is likely on a local file system

RMAN>

bash-4.3$ rman target/

Recovery Manager: Release 11.2.0.4.0 - Production on Wed Apr 5 11:32:13 2017

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: ERPDB (DBID=2929713817)

RMAN> show snapshot controlfile name;

using target database control file instead of recovery catalog

RMAN configuration parameters for database with db_unique_name erpdb are:

CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/app/oracle/product/11.2.0/db_1/dbs/snapcf_erpdb1.f'; # default

RMAN> CONFIGURE SNAPSHOT CONTROLFILE NAME TO '+DG_DATA/erpdb/controlfile/snapcf_erpdb.f';

new RMAN configuration parameters:

CONFIGURE SNAPSHOT CONTROLFILE NAME TO '+DG_DATA/erpdb/controlfile/snapcf_erpdb.f';

new RMAN configuration parameters are successfully stored

RMAN> show snapshot controlfile name;

RMAN configuration parameters for database with db_unique_name erpdb are:

CONFIGURE SNAPSHOT CONTROLFILE NAME TO '+DG_DATA/erpdb/controlfile/snapcf_erpdb.f';

RMAN> exit

Recovery Manager complete.

bash-4.3$