Database backup is like a second life for the database. It plays an important role in-case any disaster or failure occurs on the database. Restoring a corrupt or damaged database without a clean backup is like nightmare situation for database administrator but it’s possible. You can repair and restore corrupt oracle database with the help of third party oracle database recovery utility.
Oracle offers some valid methods to backing up an oracle database, those are....
- Export/ Import Method
- Cold Backup Method
- Hot Backup Method
- RMAN Backup Method
Export/Import Method: Export is a logical database backups in that they extract logical definitions and data from the database to a file.
Cold Backup Method: It is also known as off-line backup. It is performed on the database while database is unavailable for the users. To do this shutdown oracle database and take the backup of all data, control and log files. You can take the cold backup of database regardless if database is in archivelog or nonarchivelog mode.
Hot Backup Method: Also known as on-line backup of the database. It is performed on the database while database is open and available for the users. You can take hot backup of database only if database is in archivelog mode. You can't perform this while database is in nonarchivelog mode.
RMAN Backup Methods: You can use it anytime either database is on-line or off-line. It supports the backup of data, control, server parameter, archived redo log and RMAN backup files.
Attention: You can't backup network configuration file, password file with the help of RMAN backup so use any other backup method to backup these files.
Conclusion: Don't depend upon only one method; always try to maintain the backup of oracle database by more than one above mentioned methods. As you have discussed above RMAN doesn't backup the password file so in-case you have lost the password of oracle database then you can't retrieve it with this method. To do this, you should have another backup.