Backup and Recovery - Expert Consolidation in Oracle Database 12c - page 389

Note that when using RMAN in a Data Guard scenario and you intend to take the backups from your standby
database to reduce load on the primary database then the use of a catalog database is mandatory if you want to
use these backups to restore or recover the primary database. Otherwise, how could the primary “know” about the
backups taken on the standby database? Remember that backup information is always stored in the controlfile unless
the catalog is used, and controlfiles are local to each database.
While many organizations might have a non-CDB for the recovery catalog a CDB with multiple PDB sounds like
an interesting alternative.
Creating the catalog owner
The catalog owner is an arbitrary user account in a non-CDB database. Before creating it you should ensure that the
user has its own dedicated tablespace rather than using the database's default. The size of the tablespace depends on
the number of database targets and the amount of archived redo logs they produce. The catalog keeps track of every
archived log, and if you go through a lot then your catalog will grow larger. Obviously the more backups per database
you keep in the catalog the larger the catalog.
To create the catalog owner, create the tablespace first, as shown in this example:
SQL> create tablespace rman_catalog_tbs datafile size 20G
2 autoextend on next 1G maxsize 30G;
Tablespace created.
Next create the user, similar to this command:
SQL> create user rco identified by securePassword
2 default tablespace rman_catalog_tbs
3 temporary tablespace temp
4 quota unlimited on rman_catalog_tbs;
User created.
SQL> grant recovery_catalog_owner to rco;
Grant succeeded.
This concludes the actions to be taken from a privileged account. The next step is to actually create the catalog.
Creating the catalog
The next step is the creation of the catalog itself. Exit sqlplus if you have not done so already and connect to rman
using “catalog” option. It is assumed that a TNS-alias has already been defined for the recovery catalog database.
The following example uses “rcat” as the TNS-name.
[oracle@server1 ~]$ rman catalog rco@rcat
Recovery Manager: Release 12.1.0.1.0 - Production on Sat Sep 21 23:20:40 2013
Copyright (c) 1982, 2013, Oracle and/or its affiliates. All rights reserved.
recovery catalog database Password:
connected to recovery catalog database
RMAN>