Performing Oracle User-Managed Backups - OCP: Oracle Database 12c Administrator Certified Professional - page 42

Once you complete the online backup, one more very important step is to back up the
archived redo logs that were generated during the backup. You will need each log that was
generated from the time you issued the ALTER DATABASE BEGIN BACKUP command until you
issued the ALTER DATABASE END BACKUP command. After the backup, use the ALTER SYSTEM
SWITCH LOGFILE command to force a log switch to cause the current online redo log (which
contains redo generated during the backup) to be archived after you have completed the
backup. You will need the redo in this log file, and any other archived redo logs that might
have been generated during the backup, in order to recover the database from the backup
you just completed.
In addition to regular online backups, you will want to schedule regular backups of your
archived redo logs to protect them as much as possible. For example, if the online backup in
the exercise ended at 4 p.m., you would be able to restore the database up to 4 p.m. with the
archived redo logs you backed up. Archived redo logs will continue to be generated, though,
and if you want to be able to recover your database to a point beyond 5 p.m., you will need to
have those later-generated archived redo logs available (more on recovery in the next chapter).
Thus it is a good idea to have regular backups of your archived redo logs!
In Exercise 1.4, we walk you through the process of doing an online backup.
exeRCiSe 1.4
executing an Online Backup
In this exercise you will be performing an online database backup. As mentioned in the
text, your database will need to be in ARCHIVELOG mode to successfully execute this
backup.
1. We assume your database is already running in ARCHIVELOG mode. If it's not, return
to Exercise 1.1 and put your database in ARCHIVELOG mode.
2. As with the previous offline/cold backup, you need to know what data files need to be
backed up:
SQL> Select file_name from dba_data_files;
FILE_NAME
--------------------------------------------
C:\ORACLE\ORADATA\ORCL\USERS01.DBF
C:\ORACLE\ORADATA\ORCL\UNDOTBS01.DBF
C:\ORACLE\ORADATA\ORCL\SYSAUX01.DBF
C:\ORACLE\ORADATA\ORCL\SYSTEM01.DBF
C:\ORACLE\ORADATA\ORCL\REVEAL_DATA_01.DBF
C:\ORACLE\ORADATA\ORCL\REVEAL_INDEX_01.DBF
C:\ORACLE\ORADATA\ORCL\USERS02.DBF
7 rows selected.