How to enable ARCHIVELOG mode for a database

ARCHIVELOG mode has a number of benefits:

• Database can be backed up online
• Backup policy can be managed through RMAN
• Database can be recovered point-in-time

By default a database is created in NOARCHIVELOG mode. Here is a sequence of steps to perform in order to enable ARCHIVELOG mode for a database:

1. Connect as sysdba

sqlplus / as sysdba

2. Shut down the database

SHUTDOWN IMMEDIATE;

3. Modify pfile by setting LOG_ARCHIVE_START parameter to true

LOG_ARCHIVE_START=TRUE

4. Startup and mount your database using your parameter file or create spfile from your pfile and then mount

STARTUP MOUNT PFILE='/u01/app/oracle/product/11.2.0.3/dbs/init.ora';

or

CREATE SPFILE='/u01/app/oracle/product/11.2.0.3/dbs/spfile.ora' FROM PFILE='/u01/app/oracle/product/11.2.0.3/dbs/init.ora';
STARTUP MOUNT;

5. Enable ARCHIVELOG mode

ALTER DATABASE ARCHIVELOG;

6. Open your database

ALTER DATABASE OPEN;

After you ran all the above, check the status of your database with the following command:

ARCHIVE LOG LIST;

The output should look something like that:

Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     56
Next log sequence to archive   58
Current log sequence           58