Start by creating a database schema (usually called rman). Assign an
appropriate tablespace to it and grant it the recovery_catalog_owner
role. Look at this example:
sqlplus sys
SQL>create user rman identified by rman;
SQL> alter user rman default tablespace tools temporary tablespace
temp;
SQL> alter user rman quota unlimited on tools;
SQL> grant connect, resource, recovery_catalog_owner to rman;
SQL> exit;
Next, log in to rman and create the catalog schema. Prior to Oracle 8i
this was done by running the catrman.sql script. rman catalog
rman/rman
RMAN>create catalog tablespace tools;
RMAN> exit;
You can now continue by registering your databases in the catalog.
Look at this example:
rman catalog rman/rman target backdba/backdba
RMAN> register database;