Oracle raw disk image backup and restore!!

[astra]

Hello all,

I have a shared volume group for Oracle RAC datafiles. I need to create a document which describes how to recover if the share volume group vg_rac disk is crashed.

How can we take the backup of Oracle rac raw disk image and restore it as a recovery process.?

Please suggest.

Thanks in advance.

Regards,
Amit

[Steven E. Protter]

Shalom,

To be safe, use rman to back up data oracle data on raw disk areas.

I've successfully ignited and restored idle oracle databases in raw disk areas, also software ag adabas databases in such files, but its tricky and unreliable and not supported.

SEP

[Wim Rombauts]

The only way to take that kind of backup, and be sure you can restore your database with it, is to fully shut down all RAC instances and then create a copy.
But I presume that the fact that you are running RAC means that you cannot bring down the database frequently.

So then RMAN is indeed the best solution. You can create online backups of your database, and fully restore them from scratch. Explaining the exact procedure is lengthy, but when you read the RMAN guide, and preferably create an RMAN backup script, you can schedule daily backups that allow you a point-in-time restore without too much effort.

[Maxim Yakimenko]

Use Data Protector and RMAN and be lucky :)

[astra]

Hi Everyone,

Thanks for your valuable suggestions.

Our customer is reluctant to use the Data protector. Also, i think we can't use RMAN if archivelog mode is off. We are taking care of this thing separately.

With due respect i would like to ask that "Can we still use RMAN for backing and restoring raw disk image and how?"

Please look at the steps what i am planning to do in case of failure: -

DOWNTIME scenario
=================

- Get a new disk
- Create VG,LV
- Export it to other RAC nodes
- Set desired permissions
- Restore the Oracle OCR/vote from the backup taken using dd.???
- Create database from scratch using dbca.
- restore the database using the backup dump.

Please clarify and suggest if anything i am missing.


If my vg_rac disk is crashed then i think my database will stop functioining and the downtime is evitable..right? Please clarify.

Thanks
Amit

[astra]

Hi,

I mean "inevitable" :-)

[Norm Diederich]

Amit,
If you do not have archive log mode enabled, you will not be able to do a point in time recovery.

Using dd to create a backup will ONLY be able to create a consistent image if the database is DOWN.

You need to use rman with some tool such as DP to create your consistent backup image with a DB that has archive logging enabled.

Regards,
Norm

[TTr]

> I need to create a document which describes how to recover if the share volume
> How can we take the backup of Oracle rac raw disk image and restore it as a recovery process.?

Are you "puting the carriage before the horse" here? How do you run backups right now? If your current backup method can not recover a crashed raw disk then it is useless. It seems to me that any consistent offline or online backup method (RMAN is not necessary but it can definitely be used as well), can be used to recover the database. Of course the crashed disk needs to be recreated first using OS and oracle procedures.

[Maxim Yakimenko]

RMAN can work with raw devices used by Oracle as well as with Oracle datafiles placed in regular files on filesystem