RMAN is an Oracle tool for taking the backup and RECOVERING the databases. You can copy, restore, and recover datafiles, control files and archived redo LOGS (all 3 files or any one file). It has command line utility as well as GUI-based Enterprise Manager Backup. Here we are DISCUSSING the command line utility. 

For example, we have TEST and PROD databases. Here TEST is the catalog database and PROD is the target database for which the backup has to be taken. You may loose your backup if you have your catalog and target databases on the same box and the box CRASHES .So it is always advisable to keep a separate database for RMAN catalog . 

Create TWO databases. One for RMAN catalog(Test) and one target(PROD). Both the Databases should be archive log mode(for security).

RMAN is an Oracle tool for taking the backup and recovering the databases. You can copy, restore, and recover datafiles, control files and archived redo logs (all 3 files or any one file). It has command line utility as well as GUI-based Enterprise Manager Backup. Here we are discussing the command line utility. 

For example, we have TEST and PROD databases. Here TEST is the catalog database and PROD is the target database for which the backup has to be taken. You may loose your backup if you have your catalog and target databases on the same box and the box crashes .So it is always advisable to keep a separate database for RMAN catalog . 

Create two databases. One for RMAN catalog(Test) and one target(PROD). Both the Databases should be archive log mode(for security).