Terminology:
- Target database
The target database is the DB where the RMAN is going to perform the operations on. taking the backup and recovery,detection of corruption, missing files, auto backup of the control file and spfile.etc. the control file of the target database contains the structural information of the database which is used by the server session invoked by rman in backup and recovery operations.
- Auxiliary Database:
an auxiliary database is used when creating a duplicate database or performing tablespace point in time recovery.an auxiliary database can reside on the same host as its parent copy or on a different destination.
- Channel:
A channel represents one stream of data to a device type. to perform and record the backup and recovery operations the RMAN requires a link to the target database. A channel establishes this link by creating a session in the target database that is able to interface with the host file system( to interface with disks ) and the media management library( to interface with tapes).
- RMAN Repository-
RMAN maintains the metadata about the target database and its backup and recovery operations in the RMAN repository. Other than that it stores information about its own configuration settings, the target database schema, archived redo logs and all the backup files that are on the disk or tape. RMAN repository data is always stored in the control file of the target database.
- Recovery Catalog:
The RMAN repository data can optionally be kept in a recovery catalog which is a separate Oracle Database.
- Media Management Library:
Is used by RMAN when reading and writing from tapes.
- Change tracking feature:
Once we configure change tracking feature in our RMAN a new background process is available i.e CTWR.
With the help of this file, RMAN can directly go to Change Tracking File & check out the changes to be backed up, once the backup is done it leaves a bit, so that if again a backup is required then it will start the backup after that bit left.
