Enable ARCHIVELOG Mode
When you run a database in ARCHIVELOG mode, you enable the archiving of the redo log. The database control file indicates that a group of filled redo log files cannot be reused by LGWR until the group is archived. A filled group becomes available for archiving immediately after a redo log switch occurs.
The archiving of filled groups has these advantages:
- A database backup, together with online and archived redo log files, guarantees that you can recover all committed transactions in the event of an operating system or disk failure.
- If you keep an archived log, you can use a backup taken while the database is open and in normal system use.
- You can keep a standby database current with its original database by continuously applying the original archived redo logs to the standby.
You can configure an instance to archive filled redo log files automatically, or you can archive manually. For convenience and efficiency, automatic archiving is usually best. Archiver process (ARCx) writes filled redo log files to the database archived redo log.
STEPS:-
A. configure
1) alter system set db_recovery_file_dest='+ORAFLASH001' scope=both sid='*';
2) alter system set db_recovery_file_dest_size = 20G scope=both sid='*';
B. Enable Archivelog Mode
1) shutdown database
2) startup database in mount mode
3) alter database archivelog; # as sysdba
4) sys@demo> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 301
Next log sequence to archive 302
Current log sequence 302
5) alter database open;
Hope this help. Regards Rupam
