http://www.dba-oracle.com/t_rman_export_expdp.htm
Question: I've been using data pump (the export utility) to backup my database, but I wonder if I should be using RMAN instead. They both do backups, so what's the advantages of each?
Answer: Yes, RMAN and export both backup tables, and they both support flashback database, but there are some important differences:
- Data Pump Export (expdp) - The export utility is a "logical" backup, usually done by specifying specific tables. If you fail to do a "consistent" export, or if you fail to include related tables and use RESTRICTED and CONSISTENT mode (with referential integrity constraints), you may not be able to recover properly. Export is often used as a supplement to RMAN, usually for the restore of specific tables.
- Recovery manager (rman) - RMAN is designed for backup and recovery, a extension of the Enterprise Backup Utility (EBU). RMAN takes full, physical, consistent backups of your database files..
Advantages & disadvantages of Export:
- Free, and easy to use
- Very slow, compared to RMAN (examines every data block)
- Easy restore of a specific table
- Does not require ARCHIVELOG mode
Advantages & disadvantages of RMAN:
- RMAN has block-level media recovery
- Has a catalog for backup tracking and a report utility
- Fast - If you dedicate a backup device for each production disk, you can backup terabytes in the time it takes to backup any single disk.
- Does hot or cold backups
- Backups and restores can be done in parallel
- Allows incremental backups (block change tracking)
- Interfaces with media management systems (TMS)