Backup and Recovery - Expert Consolidation in Oracle Database 12c - page 398

Backup validate will not generate any backup set files, and any findings will go into v$database_block_
corruption as well as the alert.log in addition to those that you see on screen. In the unfortunate event that more
than one corruption is expected, you should set the tolerance towards detected corruption higher using the set
maxcorrupt to a high number, indicating how many corruptions can be reported before the command aborts.
Restore and Recovery
The foundation of successful restores and recovery operations of a database are manifold. Well-trained staff, good written
procedures, and the ability to keep a cool head all help the database administrator during the difficulties when restoring a
database. With the previous section about backups the second essential success factor should have been covered as well.
There are many ways to restore a database—fully or parts—and recover it. The procedure chosen depends on
the failure that has occurred. Oracle provides a system of identifying failures since version 11.1, called the Data
Recovery Advisor. In some situations it can be sufficient to invoke it to get to a solution. If for example, a PDB
“loses” a data file you will be informed by the database that a new failure has been detected. As soon as a user tries
to access a data file, the failure becomes apparent. After the monitoring tool picked the missing file up, you can
connect to RMAN and list the failures:
RMAN> list failure;
Database Role: PRIMARY
List of Database Failures
=========================
Failure ID Priority Status Time Detected Summary
---------- -------- --------- ---------------- -------
8 HIGH OPEN 22.09.2013 19:30 One or more non-system datafiles are missing
The message leaves little for interpretation: a data file is missing. Now let's see what the advisor has to offer:
RMAN> advise failure 8;
Database Role: PRIMARY
List of Database Failures
=========================
Failure ID Priority Status Time Detected Summary
---------- -------- --------- ---------------- -------
8 HIGH OPEN 22.09.2013 19:30 One or more non-system datafiles are missing
analyzing automatic repair options; this may take some time
using channel ORA_DISK_1
using channel ORA_DISK_2
using channel ORA_DISK_3
using channel ORA_DISK_4
analyzing automatic repair options complete
Mandatory Manual Actions
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no manual actions available