Configuring the Database Archiving Mode
Why we need Archiving mode enable?
To back up the database while it is open (database open mode), or to be able to perform complete or point-in-time media recovery, you must enable the archiving of redo log files. To do so, you place the database in ARCHIVELOG
mode.
The database can be initially created in ARCHIVELOG mode, but it is configured for NOARCHIVELOG mode by default.
How to check Archive log mode enable or not?
SQL> select sequence#, bytes,archived,status,first_time,next_time from v$log;
SQL> archive log list
SQL> select log_mode from v$database;
NOARCHIVELOG Mode
By default, a database is created in NOARCHIVELOG mode. The characteristics of operating a database in NOARCHIVELOG mode are as follows:
Redo log files are used in a circular fashion.
Impacts of NOARCHIVELOG Mode
If a tablespace becomes unavailable because of a failure, you cannot continue to operate the database until the tablespace has been dropped or the entire database has been restored from backups (Cold backup).
Media Recovery Options in Archive log mode
You can restore a backup copy of the damaged files and use archived log files to bring the datafiles up-to-date while the database is online or offline.
Changing the Archiving Mode
Shut down the database
SQL> shut immediate;
Start the database in Mount state so that you can alter the Archivelog mode of database
SQL> startup mount
Set the database in Archivelog mode by using the ALTER DATABASE command
SQL> alter database archivelog;
Open the database
SQL> alter database open;
Check Archive log mode enable or not
SQL> archive log list
SQL> select log_mode from v$database;
I hope above guide is helpful to all of you and you are able to enable archivelog mode. Share this awesome article to your friends as well. Have a nice day.