How to enable the archivelog in oracle

                                                   Enabling archive log


Below are the steps for enabling the archive log.


Verify the log mode


[oracle@oracle dbs]$ sqlplus

SQL*Plus: Release 12.1.0.2.0 Production on Thu Feb 9 09:49:48 2017

Copyright (c) 1982, 2014, Oracle.  All rights reserved.

Enter user-name: / as sysdba

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics
and Real Application Testing options

SQL> archive log list;
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     14
Current log sequence           16
Here archive log mode disabled for this database.


By default archive destination will be db recovery dest only.Now we need to bring down the database and then mount the same.


SQL> shut immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area  754974720 bytes
Fixed Size                  2928968 bytes
Variable Size             578817720 bytes
Database Buffers          167772160 bytes
Redo Buffers                5455872 bytes
Database mounted.

 Now we enabling the archive log.


SQL> alter database archivelog;

Database altered.

after disable the archive open the database.


SQL> alter database open;

Database altered.

 Now check the log mode.it will be enabled mode.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     14
Next log sequence to archive   16
Current log sequence           16