Recovering After the Loss of Datafiles: Scenarios

If a media failure affects datafiles, then the recovery procedure depends on:

The archiving mode of the database: ARCHIVELOG or NOARCHIVELOG
The type of media failure
The files affected by the media failure

Losing Datafiles in NOARCHIVELOG Mode

If either a permanent or temporary media failure affects any datafiles of a database operating in NOARCHIVELOG mode, then the database automatically shuts down.

If the media failure is temporary, correct the underlying problem and restart the database. Usually, crash recovery will recover all committed transactions from the online redo log. If the media failure is permanent, then restore the database as described in "Recovering a Database in NOARCHIVELOG Mode".

Losing Datafiles in ARCHIVELOG Mode

If either a permanent or temporary media failure affects the datafiles of a database operating in ARCHIVELOG mode, then the following scenarios can occur.

Damaged Datafiles	Database Status	Solution
Datafiles in the `SYSTEM` tablespace or datafiles with active undo segments.	Database shuts down.	If the hardware problem is temporary, then fix it and restart the database. Usually, crash recovery recovers lost transactions. If the hardware problem is permanent, then recover the database as described in "Performing Closed Database Recovery".
Datafiles not in the `SYSTEM` tablespace or datafiles that do not contain active rollback or undo segments.	Affected datafiles are taken offline, but the database stays open.	If the unaffected portions of the database must remain available, then do not shut down the database. Take tablespaces containing problem datafiles offline using the temporary option, then recover them as described in "Performing Datafile Recovery in an Open Database".