Overview of RMAN Recovery Catalog

 RMAN Recovery catalog is a schema that is created in separate DB.

It contained RMAN metadata obtained from the target database control file.

RMAN stores, uses, and maintains the information in the recovery catalog.

The recovery catalog is maintained by RMAN when you do following

Register the target database in catalog

Resynchronize the catalog with control file of target DB

Change the information about the backups or files.

Perform backup,restore,recovery operations

 

RMAN Catalog Contents

Datafile and archived redo log file backup sets and backup pieces.

Datafile copies

Archive and redo log files

The physical structure of the target database.

 

Why use a recovery catalog?

It makes restore if all the target database is lost, including the controlfile.

As that controlfile contains all backup information, the catalog would then be used to identify a controlfile backup

If an RMAN catalog is not used, the controlfile autobackup should be configured to ON. There are some features which are only supported using an RMAN catalog

How to create Recovery Catalog

Create default table space for the catalog

SQL>create tablespace catalogtbs

Datafile ‘/oracle/oradata/VIS/catalogtbs_01.dbf’

size 500M;

 

Create the Recover catalog schema

SQL>create user rman identified by rman

Default tablespace catalogtbs

Quota unlimited on catalogtbs;

 

Grant the User privilege

SQL> Grant recovery_catalog_owner to rman;

SQL> Grant connect, resource to rman;

 

Creating the recovery catalog

Connect RMAN catalog database and Before creating the recovery catalog make sure to have the tnsnames.ora entry for the catalog database in the target server and the listener must be up and running in the catalog database server

You must be able to connect to the catalog database from sqlplus from the target server.

Example

RMAN catalog <catalog username>/<password> @<catalog db connect string>

RMAN> connect catalog rman/rman@catdb

RMAN> create catalog;

 

Recovery catalog Views

RC_DATABASE

RC_DATAFILE

RC_STORED_SCRIPT

RC_TABLESPACE

Catalog database Frequently Asked Questions

1. What is Catalog database and How to Configure it ? 

This is a separate database which contains catalog schema. You can use the same target database as the catalog database but its not at all recommended

2. How Many catalog database I can have?   

You can have multiple catalog database for the same target database . But at a time you can connect to only 1 catalog database via RMAN. Its not recommended to have multiple catalog database.

3. Is this mandatory to use catalog database ?   

No ! its a optional one.

4. What is the advantage of catalog database ?   

Catalog database is a secondary storage of backup metadata. Its very useful in case you lost the current controlfile, as all the backup information are there in the catalog schema. Secondly from contolfile the older backup information are aged out depending upon the control_file_record_keep_time. RMAN catalog database mainten the history of data. Kindly refer the note <> for more details on relation between  retention policy and control_File_record_keep_time.

5. What is the difference between catalog database & catalog schema ?  

Catalog database is like any other database which contains the RMAN catalog user's schema.

6. What happen if catalog database lost ?   

Since catalog database is a option one there is no direct effect  of loss of catalog  database. Create  a new catalog database and register the target database with the newly createdcatalog one. All the backup information from the target database current controlfile will be updated to the catalog schema. If any backup information which is aged out from the target database then you need to manually catalog those backup pieces.

Reference:

RMAN Overview

Loss of a Non system Data file recovery scenarios

Archive log Basic

Difference between RMAN Validate and crosscheck