ORA-00245: control file backup operation failed

Applies to:
Oracle Server - Enterprise Edition - Version: 11.2.0.2 and later   [Release: 11.2 and later ]
Information in this document applies to any platform.

Symptoms
RMAN Backup on RAC database fails when doing controlfile autobackup fails with error:


RMAN-00571: =========================================================== 
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== 
RMAN-00571: =========================================================== 
RMAN-03009: failure of Control File and SPFILE Autobackup command on 
ORA_DISK_1 channel at 11/27/2010 10:00:31 
ORA-00245: control file backup operation failed

SQLPLUS controlfile backup  also fails with:


alter database backup controlfile to '/oracle/backup_cntl_file' *
ERROR at line 1:
ORA-00245: control file backup operation failed

Changes
RAC Database  release 11.2 
 
Cause
The error description is:

00245, 00000, "control file backup failed; target is likely on a local file system"
 // *Cause: Failed to create a control file backup because some process
 // signaled an error during backup creation. This is likely caused
 // by the backup target being on a local file system so it could not
 // be accessed by other instances. It can also be caused by other
 // I/O errors to the backup target. Any process of any instance that
 // starts a read/write control file transaction must have access
 // to the backup control file during backup creation.
 // *Action: Check alert files of all instances for further information.
 
RMAN creates a copy of the control file for read consistency, this is the snapshot controlfile. 
Due to the changes made to the controlfile backup mechanism in 11gR2 any instances 
in the cluster may write to the snapshot controlfile. Therefore, 
the snapshot controlfile file needs to be visible to all instances.

The same happens when a backup of the controlfile is 
created directly from sqlplus any instance in the cluster may write to the backup controfile file.

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:
RMAN> CONFIGURE SNAPSHOT CONTROLFILE NAME TO '<shared_disk>/snapcf_<DBNAME>.f';