Wednesday, May 15, 2013

Overview of hot and cold backup in Oracle

Backups either hot or cold are taken to protect database from media failure. Oracle provides different types of backups, you can use the one that satisfies your business requirement. Here I will discuss about hot and cold backup.

Cold backup: Cold backup is the physical backup of database and taken when database is in offline mode(shutdown). The database must be shutdown using the SHUTDOWN NORMAL command.
After shutdown the system copy all the control files, datafiles, online redo files and init.ora files to a safe location. Cold backup is basically an exact copy of the database. You can move this copy to another computer having same OS. The advantage of taking cold backup is that you can easily monitor the backup and recovery process. Use cold backup if your business can afford some downtime for backup.

Hot backup: Hot backup is taken when the database is in online mode(running). To perform hot backup your database must be in archive mode. When the hot backup is performed database remains available for use and once it is started you can't shutdown the database. In hot backup also an exact copy of the database is being created. During backup it might be possible that your database also change so it is important to save the log file that contain the changes. The main advantage of taking hot backup is that you can work on your database while backup is being performed and you can also recover your database at any point in time. Use hot backup when a full backup of your database is needed.

No comments:

Post a Comment