ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode

The backup of database fails with following error:-
ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode

[oracle@oel6 ~]$ rman target /

Recovery Manager: Release 11.2.0.4.0 - Production on Thu Oct 22 21:22:26 2015

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

connected to target database: TESTDB (DBID=2675922698)

RMAN> backup database;

Starting backup at 22-OCT-15
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=43 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 10/22/2015 21:26:42
ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode
continuing other job steps, job failed will not be re-run
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 22-OCT-15
channel ORA_DISK_1: finished piece 1 at 22-OCT-15
piece handle=/u01/app/backup/1sqkcick_1_1 tag=TAG20151022T212639 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:07
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================

RMAN-03009: failure of backup command on ORA_DISK_1 channel at 10/22/2015 21:26:42
ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode

RMAN>

This is because we cannot take online backup of datafiles when database is in NOARCHIVELOG mode.

[oracle@oel6 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Thu Oct 22 21:35:38 2015

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, Automatic Storage Management, OLAP, Data Mining

and Real Application Testing options

SQL> select log_mode from v$database;

LOG_MODE

------------

NOARCHIVELOG

SQL> 

The solution is to place the database into ARCHIVELOG mode.