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In Oracle, Flashback is used to recover the database to a particular point.

If it is so, what is the need for backup and recovery? Since flashback itself can achieve the recovery of database what is the need for backup and recovery feature of RMAN in oracle?

Mureinik
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Avinash
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3 Answers3

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First, the retention of the flashback is limited (by the size of the undo tablespace, e.g.). Second, and more importantly - flashback is done against the same database. If you have a hardware failure on your storage device, the flashback will be corrupted just like the rest of the database. Backups, on the other hand, should be made to a different storage device.

Mureinik
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Flashback only preserves transaction data, and only - for most people - for a few minutes or hours at most. It cannot be used to restore corrupted data files or to reload entire tables, only to rollback or recover very recent transactions. Running in archivelog mode with proper backups - physical (RMAN) and logical (datapump) - is necessary if you want real protection.

pmdba
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First of all, please keep in mind that Oracle Flashback is a name for Family of techniques (Flashback database, Flashback drop, Flashback query ... ).

You mention that Recovering DB to a paticular point - so I guest that you're mentioning "Flashback Database". There are some limitations with Flashback Database ralating to dropped datafile, NOLOGGING operations, ...

RMAN (with appropriate configuration) doesn't fear dropped datafile, NOLOGGING operations, ... at all! :)

Duong
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