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restore failier

Former Member
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what happens if we do not able to restore database from offline backup media(if our hard disk is not working properly)?

Accepted Solutions (1)

Accepted Solutions (1)

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I'm not sure how you mean this question. I try to answere several details as I understand it.

Assuming you database is running in archive log mode.

a) If you have a backup and the disk you want to restore is damaged - repair the disk and restore the database. You will get a problem if the online redologs are lost. These transaction you will lost, because they are not written to the archive. In standard installations these files are mirrored on different disks. If they are not mirrored and together with the database on the same devices you will lost these transacations.

If they are located on different disks (not together with database files) you can restore the database and recover all offline archives. During the next normal database start, ORACLE will reply all transactions from the online redologs. If that is possible you will have your database back and no data are lost.

Temperary tablespaces are not backed up an need to be recreated after the database restore.

b) If you backup is damaged , try to restore an older backup and recover all archive sincs that backup.

If the database is running in noarchive log mode.

Restore the backup and open the database with 'RESETLOGS'. You will get the database back on the date of the backup. All transaction after the backup are lost.

So you see, it is very importend how to setup you database for production systems.

Here my commandation, based on 20 years experience in ORACLE and SAP.

1) Place the origlog an mirrlog on different disks.

2) Define three copies of the ORACLE controlfile and place them on different disks

3) Run the database in archive log mode and if possilbe save them twice on different tapes.

4) Keep the database bakups and archive backup availailbe over at least 21 days.

5) Run daily backups, online or offline.

7) Craete a babkup of the controlfile to trace once a week and after changeing the database.

7) Check the ORACLE dictionary consistency once a week or at least once during backup life time.

I hope this will answere your question.

Best regards

Ulrich Henkenjohann

Answers (1)

Answers (1)

Active Contributor
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what happens?

you cannot restore... your system is not up... and lose your job!