Loss of
a Data File in NOARCHIVELOG Mode
The loss of any data file
from a database in NOARCHIVELOG mode requires complete restoration of the
database, including control files and all data files.
With the database in NOARCHIVELOG mode, recovery is possible only up to
the time of the last backup. So users must reenter all changes made since that
backup.
To perform this type of recovery:
1. Shut down the instance if
it is not already down.
2. Click Perform Recovery on
the Maintenance properties page.
3. Select Whole Database as
the type of recovery.
If you have a database in NOARCHIVELOG mode that has an incremental
backup strategy, RMAN first restores the most recent level 0 and then RMAN
recovery applies the incremental backups.
Loss of
a Noncritical Data File in ARCHIVELOG Mode
With the
database in ARCHIVELOG mode, the loss of any data file not belonging to the SYSTEM
or UNDO tablespaces affects only the objects that are in the missing file. The
rest of the database remains available for users to continue work.
To restore
and recover the missing data file:
1. Click Perform Recovery on the Maintenance
properties page.
2. Select Datafiles as the recovery type,
and then select “Restore to current time.”
3. Add all data files that need recovery.
4. Determine whether you want to restore the
files to the default location or (if a disk or controller is missing) to a new
location.
5. Submit the RMAN job to restore and
recover the missing files.
Because the
database is in ARCHIVELOG mode, recovery is possible up to the time of the last
commit and users are not required to reenter any data.
Loss of
a System-Critical Data File in ARCHIVELOG Mode
Data files
belonging to the SYSTEM tablespace or containing UNDO data are considered
system critical. A loss of one of these files requires the database to be
restored from the MOUNT state (unlike other data files that may be restored
with the database open).
To perform
this recovery:
1. If the instance is not already shut down,
shut it down.
2. Mount the database.
3. Click Perform Recovery on the Maintenance
properties page.
4. Select Datafiles as the recovery type,
and then select “Restore to current time.”
5. Add all data files that need recovery.
6. Determine whether you want to restore the
files to the default location or (if a disk or controller is missing) to a new
location.
7. Submit the RMAN job to restore and
recover the missing files.
8. Open the database. Users are not required
to reenter data because the recovery is up to the time of the last commit.
Read more about data file:
