Databases Reference
In-Depth Information
Loss of a non-critical datafile
From the Oracle perspective a non critical file is a file that does not prevent the
database from being opened if it is taken off line. Certainly, the DBA must assess
how critical a datafile is from the business' perspective. However, technically
speaking Oracle can be operational if a non-critical datafile is damaged.
When a non-critical datafile is missing, the procedure to bring back the database to
the open state and fully recovered is as follows:
1. Try to open the database. As at least one datafile is missing the Oracle
instance won't open the database and an error will be displayed.
2. Identify the missing data files.
3. Proceed to restore the previously identified data files from a valid backup.
4. At this point it is up to the DBA to put offline the restored datafiles and open
the database or just proceed to the recover process
5. Recover the datafile or datafiles.
6.
If the database was open before the recover process was executed on the
problematic data files then just put online the recovered data files. Otherwise,
if the database was left in a mount state then proceed to open the database
once the recover process is finished.
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