Oracle Database migration to a remote Data Protector cell--Best practices

5. Startup nomount force: at this point, we want to have the instance running with the previously

restored SPFILE. If you wish, you could also specify the SPFILE location in the startup

command.

6. Restore the control files using RMAN

7. Mount the database: using the previously restored control files.

8. Query the control files for available backup information; decide on the Point In Time Recovery

9. Restore and Recover the database until the Point in Time (PITR)

10. Open the database with the Reset logs option

Important Note:

When performing a SPFILE or Control File restore from autobackup, in

cases where the search of the backup set seems to take longer than

expected, it is recommended to use the following omnirc variable on the

server performing the restore:

OB2RETRYCOUNT=1

This variable reduces the loop iterations when searching for the

autobackup.

All sessions reports are in the Appendix fully listed

Validating RMAN Backups

Oracle RMAN offers two powerful commands to help us detecting physical block corruption on

our backups:

• BACKUP […] VALIDATE

RMAN will read the specified datafiles and ensure there is no corruption

• RESTORE […] VALIDATE

As for the Backup validate, RMAN will read the content of the backup (from disk or tape) and verify

there is no corruption.

It is also a method to verify the backup performance in our environment. While a backup validate will

read the blocks into memory, it will not write the Backupset to disk or tape. This can help us to

compare the time with a streaming backup to tape and verify where the time is spent.

When planning a restore of your database, remember to include a RESTORE VALIDATE in your

restore procedure. This way, you can verify in advance, if the media to be shipped/copied is valid

Under some circumstances, it may happen that your backup data on tape or disk is corrupted. This

can be caused by bad tape library firmware, network/SAN issues or even defect tapes. It is very

uncommon but possible.

During backup, RMAN cannot verify the integrity of every single block written to the backup device. Thus,

it may happen that an RMAN successful backup is not usable as one or more data blocks are corrupt.

In this case, the RESTORE VALIDATE option may help you identify the usability of the backup before

performing the actual restore.