RMAN Configuration Demystified: A Practical Deep Dive for DBAs – Part 1

 

RMAN Configuration Demystified: A Practical Deep Dive for DBAs – Part 1

 

rman TARGET SYS/target_pwd@target_str

 

Explanation:

• This command starts RMAN and connects only to the target database, using the credentials provided.
• Since there's no CATALOG clause, this is a NOCATALOG mode backup/restore operation.
• target_pwd is the password of the SYS user, and target_str is the TNS alias (or connection string) of the target database.

Use Case:

Used for RMAN operations without a recovery catalog. The control file is used to store backup metadata.

 

rman TARGET / CATALOG rman/rman@rcat

 

Explanation:

• Connects to the target database using OS authentication (TARGET /) — assuming the user has SYSDBA privilege.
• Connects to the recovery catalog database using the user rman with password rman and TNS alias rcat.

Use Case:

Used when backup metadata is maintained in a Recovery Catalog (preferred for environments with multiple databases or long backup retention policies).

 

rman TARGET / CATALOG rman/rman@rcat AUXILIARY sys/aux_pwd@aux_str

 

First let’s crack what is TARGET , CATALOG and AUXILIARY

TARGET Database :

This is the main database you want to back up, restore, or recover.

It is the primary subject of all RMAN operations.

You must always connect to a target database, even if using a recovery catalog.

E.g.

rman TARGET sys/password@orcl

rman TARGET /

 

CATALOG Database(Recovery Catalog)  :

The Recovery Catalog is an optional separate database schema (often in a dedicated database) that stores RMAN metadata.

It offers more advanced reporting, longer metadata retention, and can manage multiple target databases.

E.g.

rman TARGET / CATALOG rman/rman@rcat

rman/rman@rcat is the connection to the Recovery Catalog stored in the rcat database.

 

AUXILIARY Database:

The AUXILIARY is a secondary or temporary database used for specific RMAN operations

E.g.

rman TARGET / CATALOG rman/rman@rcat AUXILIARY sys/aux_pwd@aux_str

 

Explanation:

• Connects to:
• TARGET database via OS authentication.
• CATALOG database using rman user.
• AUXILIARY database using SYS user with password aux_pwd and TNS alias aux_str.

Use Case:

Used for operations that involve a secondary (auxiliary) database, such as:

• Duplicating a database (cloning).
• Tablespace point-in-time recovery (TSPITR).
• Database point-in-time recovery (DBPITR).
• Restore and recovery to an alternate location.

 

RMAN >CONFIGURE CHANNEL DEVICE TYPE sbt CLEAR;

 

• Clears any custom channel configuration for SBT (tape) backups.

 

RMAN >CONFIGURE RETENTION POLICY CLEAR;

 

• Removes the existing retention policy setting.

 

RMAN >CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK CLEAR;

 

·         Clears the control file autobackup format setting for disk.

 

RMAN >CONFIGURE DEFAULT DEVICE TYPE TO DISK/SBT;

 

·         Sets the default device for RMAN backups.

·         DISK: Backups go to file system.

·         SBT: Backups go to tape (e.g., via third-party software like NetBackup).

 

RMAN >CONFIGURE RETENTION POLICY TO REDUNDANCY 3;

 

·         Redundancy in RMAN means how many copies of a distinct backup RMAN should retain at minimum.

·         When you set REDUNDANCY 3, you're telling RMAN:

"Keep at least 3 full backups of each datafile. If there are more than 3, the older ones can be marked obsolete."

RMAN >CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 4 DAYS;

 

·         RMAN will retain all backup sets (datafiles, control files, archived logs, etc.) that are required to perform a point-in-time recovery to any time in the last 4 days.

·         Older backups beyond the 4-day window are considered obsolete and can be deleted.