Duplicating Database without connecting to Target Database or Catalog Database
In Oracle 10g version or earlier, while duplicating a database using RMAN, we had to connect to the Target database along with the Auxiliary Database. In oracle 11g, there is a new feature available, where in the duplication from the Target Database to the Auxiliary Database can be done using RMAN without connecting to the Target database or to the Catalog Database. Only thing what is required the full backup of the Target database.
You can use the below command for using this
rman auxiliary /
>duplicate database to newname from backup location '';
This will remove the dependency of you connecting to target datbase and will make you feel more comfortable when duplicating PROD database .
I have not personally done this, however, you need 11gR2. 11gR1 doesn't have this feature. You also need an RMAN catalog. Hence you connect to the RMAN catalog, then you connect to the auxilary. The RMAN catalog knows where the RMAN backup is kept for the database that you are connecting from. If you do a lot of cloning you want to use the nid command to change the dbid of every database when you clone it, then register the cloned database after changing the dbid. RMAN uses dbid to distinguish one database from another. So if everyone of your databases is called "database" as long as you set the dbid in RMAN and the dbid is unique for each "database" RMAN will know which database you are trying to clone. If you have two databases with the same dbid RMAN will get confused and this probably won't work.