Oracle Recovery

[Former Member]

Hi,

We have an issue in our production system wherein the last Full backup scheduled on 27th Jan got failed (due to Block Corruption), but the incremental backup got successful.  (Last successfull Full Online Backup Successful on 20th Jan).

Now, to fix the block corruption issue, we have to perform some changes at the DB level, which seems to be a complex task (we have the task list).

My question is that, since the last Full Online backup got failed, can we take Full Online backup of 20th and the subsequent incremental backups (+incremental backups after the Failed full Online Backup) to recover the database, in case we face some major issues during the activity and need to recover,

Appreciate your kind support for same.

Best Regards,

Vinod

[janos_mucsi-besze]

Hi Nagan.

Yes, you can, but first validate the restore and recovery on a separate machine to make sure you can really use. Ayway, this procedure would be good to test the restore/recovery if there would be any issue during the "real" restore/recovery.

Stefan has right. You could use RMAN block recovery as well.

Just please don't forget to check the hardware with a certified hardware vendor. It does not make any sense to perform the restore/recovery if the hardware is still faulty. Otherwise the corruption will spread accross the whole system.

Regards,

János

[stefan_koehler]

Hi Vinod,

>> can we take Full Online backup of 20th and the subsequent incremental backups (+incremental backups after the Failed full Online Backup) to recover the database

Yes, you can in general. However too many information is missing to answer your question properly. I assume you are using RMAN as the block corruption was determined by backup and you are using incremental backups. So it is important to know, if you are using BCT as well (8 bitmap limit).

Otherwise, if this is just a physical block corruption - why not just using a simple RMAN block recovery for that? Not really complex and risky at all - just a single RMAN command.

Regards

Stefan

[former_member207186]

Hi,

As far as I know an incremental database backup backs up all database blocks that have changed since the last full backup and NOT the last sucessfull full backup. So to recover the database with incremental backup you must always have the preceding full backup as well.

To handle the block corruption issue, please also refer to SAP Notes:

#365481 - "Block corruptions"

#23345 - "Consistency check of ORACLE database"

#1559652 - "How to deal with block corruptions on Oracle"

Also note that in case of restore/reccovery a corruption-free (valid) backup have to be used.

Regards,

Bíborka

[manumohandas82]

Incremental Backs are backups since your last successful full online backup . Hence believe you will be able to recover with your last successful backup + very recent incremental backup + logs after the last incremental backup

Thanks ,

Manu

[Former Member]

You should be able to restore from the 20th online backup until today as long as you have all the offline log files. The restore time may be bit longer and it depends on the number of logs you need to apply to recover the database.

See note 1559652 - How to deal with block corruptions on Oracle for more details.