Oracle Archivelog Mode

 Oracle Database lets you save filled groups of redo log files to one or more offline destinations, known collectively as the archived redo log, or more simply the archive log. The process of turning redo log files into archived redo log files is called archiving. This process is only possible if the database is running in ARCHIVELOG mode. 

Checking Archivelog Mode:

Use below command to check the archivelog mode inside the oracle database.

SQL> archive log list;

You can also use below command.

SQL> SELECT LOG_MODE FROM SYS.V$DATABASE;

 

Set Archivelog Destination:

You must set a destination for archivelog files.

Create a directory for archivelog files.

$ mkdir /u01/oradata/archive

Change the parameter for archivelog destination.

SQL> alter system set log_archive_dest_1='location=/u01/oradata/archive';

Enable Archivelog Mode:

Please note that in order to enable archivelog mode, you must bounce the database

SQL> Shut immediate;
SQL> Startup mount;
SQL> alter database archivelog;
SQL> alter database open;
SQL> archive log list;
 

Archivelog mode is enabled. Run the below commands to check the archivelog mode.

 SQL> archive log list;

 

 SQL> SELECT LOG_MODE FROM SYS.V$DATABASE;

Performing Log Switch:

While your database is running in archivelog mode, you can perform force log switch. This will archive the current redo log file and force LGWR to start over-writing other redo log member

SQL> alter system switch logfile;

 

Disable Archivelog mode:

For disabling archivelog mode please run the below commands.

Please note that in order to disable archivelog mode, you must bounce the database 

SQL> shut immediate;
SQL> startup mount;
SQL> alter database noarchivelog;
SQL> alter database open;
SQL> archive log list;
 

 Thank You