Introduction to Oracle NOARCHIVELOG Database Recovery
This module introduces the concept of database recovery and the data structures required to achieve this.
The methods for restoring and recovering a NOARCHIVELOG database are the focus of this module.
After completing this module, you will be able to:
- Identify data structures required for recovery
- Identify data structures required for restoring a NOARCHIVELOG database
- Describe the implications of media failure with a NOARCHIVELOG database
- Recover a NOARCHIVELOG database
- Restore files to a different location if media failure occurs
The next lesson describes the data structures required in a recovery process.
RMAN Backup, Restore and Recover the Noarchivelog Database
Oracle strongly recommends running the database in archivelog mode.
If you do not run the database in archivelog mode, you cannot recover the database and apply changes to the restored datafiles due to missing archived redo log files.
From RMAN, you cannot make a backup of the database when it is open.
If you attempt to make a backup of the database when it is open, the following error will occur:
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 10/21/2010 11:01:46
ORA-19602: cannot backup or copy active file in noarchivelog mode
Backup Database from mount stage
However, it is possible to backup the database from mount stage
and even apply incremental backups
and recover it to specific points in time.
In the following scenario, we are going to perform the following steps to understand how the backup of the noarchivelog database
could be restored and recovered.
- Backup the database running in noarchivelog mode
- Make some changes to the database and do an incremental backup
- Rename the folder which contains all physical files of the database
- Restore the backup and recover
Here are the steps in detail:
- Back up the database. Before implementing a backup, make sure you have configured RMAN to perform an automatic backup of the control file. It will help us to easily restore the control file.
- Connect to RMAN and run the following commands: