ORA-27211: Failed to load Media Management Library

##########################
## Error
##########################

ORA-27211: Failed to load Media Management Library

### Full Error

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 08/29/2013 10:09:21
ORA-19554: error allocating device, device type: SBT_TAPE, device name:
ORA-27211: Failed to load Media Management Library
Additional information: 2

##########################
#  Error Occurred
##########################

Error occured while a backup was fired in one of the database of 11.2.0.3.0 version

##########################
## Command Executed
##########################

In RMAN,

backup archivelog logseq 5432 thread 1;

##########################
## Issue Description.
##########################

### 11.2.0.3.0


RMAN> backup archivelog logseq 5432 thread 1;

Starting backup at 29-AUG-13
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 08/29/2013 10:09:21
ORA-19554: error allocating device, device type: SBT_TAPE, device name:
ORA-27211: Failed to load Media Management Library
Additional information: 2

This database was failed over from hostp02 to hostp03 due to some issue. Backup was working fine in hostp02 server. backup is not working after failover
to hostp03 server.

While checking found that libobk.so64 library of netbackup is not linked to oracle libraries.

oralin_2 @ hostp03:/u01/app/oracle/product/11.2/db_10/lib
> ls libob*
ls: libob*: No such file or directory

##########################
## Solution
##########################

So Created a symbolic link in $ORACLE_HOME/lib location and tested the backup and it worked fine.

ln -s /usr/openv/netbackup/bin/libobk.so64 libobk.so

oralin_2 @ hostp03:/u01/app/oracle/product/11.2/db_10/lib
> ln -s /usr/openv/netbackup/bin/libobk.so64 libobk.so

oralin_2 @ hostp03:/u01/app/oracle/product/11.2/db_10/lib
> ls -ltr libob*
lrwxrwxrwx 1 oracle oinstall 36 Aug 29 09:32 libobk.so -> /usr/openv/netbackup/bin/libobk.so64
oralin_2 @ hostp03:/u01/app/oracle/product/11.2/db_10/lib

RMAN>  backup archivelog logseq 5432 thread 1;

Starting backup at 29-AUG-13
allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: SID=2799 instance=oralin_1 device type=SBT_TAPE
channel ORA_SBT_TAPE_1: Veritas NetBackup for Oracle - Release 7.1 (2011020316)