At a minimum, the environment for RMAN requires:

·         The target database that is required to be backed up

·         The RMAN client

Other optional components are:

·         Media Management Software

·         Flash Recovery Area

·         Recovery Catalog Database

Target Database

It is the database which needs to be backed up, restored or recovered using RMAN. The target database's control file is used by RMAN to gather information about the target database and to store information about RMAN's own operations.

RMAN Client

It is here where RMAN commands and SQL statements can be issued for performing backup and restoring operations. RMAN client uses Oracle Net to connect to the target database. So locating a RMAN client to any host that is connected to the target host through Oracle Net will do the job.

The above two are the required components for performing backup or restoring using RMAN. The components described below are the optional components.

Media Management Software

Media management software is used by RMAN to handle sequential media devices (for example: tape libraries, etc.).The media manager controls these devices during backup and recovery operations. It manages the loading, labeling, unloading of media, among all other functions performed by it. Actually, what happens during backup or restore operation, RMAN client get connected to target instance and it is this instance which is directed to communicate with the media manger. So instead of having a direct communication between RMAN client and media manager, the communication happens through the target instance.

Flash Recovery Area

RMAN has a feature known as Automatic Disk-based Backup and Recovery that manages all the related files of backup and recovery in a flash recovery area. This feature thus simplifies managing disk space and files related to backup and recovery operations. The flash recovery area parameter can be set using:

·         db_recovery_file_dest – This parameter determines the location of the flash recovery area.

·         db_recovery_file_dest_size – This parameter determines how much space can be used by Oracle in the flash recovery area.

There can be a need to assign flash recovery area more space, which typically depends on:

·         The size of the database

·         The number of backups one wants or requires to keep

·         If the database is being run in ARCHIVELOG mode

Recovery Catalog Database

The Recovery catalog can be used to hold RMAN repository records, RMAN stored scripts, and the sequences of RMAN commands for common backup tasks. Actually, it can be more convenient to work with the centralized store of scripts than working with command files.