Partial or targeted restore and rollforward recovery
When you??™re running the Oracle database in ARCHIVELOG mode, you can
restore only the damaged datafile(s) and can apply redo log information from the
time the backup was taken to the point of failure. The archived and online redo
logs reproduce all the changes to the restored datafiles to bring them up to the
same point in time as the rest of the database. This procedure minimizes the
time for the restore and recovery operations. Partial recovery like this can be
done with the database down. Alternatively, the affected tablespace(s) can be
placed offline and recovery can be performed with the rest of the database available.
Oracle9i improved the granularity of the recovery process by also enabling
restore and recovery of individual data blocks instead of providing restore and
recovery only of entire datafiles. Figure 11-9 illustrates backup and recovery with
archived redo logs.
Recovering from Failures | 277
Obviously, the redo logs are extremely important. Oracle first enabled analysis of
these files through the LogMiner tool in Oracle8i.
Pages:
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606