Backup ASM database

miyahira
miyahira used Ask the Experts™
on
Hello,

We have Oracle RAC 11gR2 on Windows Server 2008, two nodes, and database is in a 2TB storage with ASM filesystem. The redologs, control files and datafiles are stored in ASM.

As I read once, a DBA should be paranoic. So, I'm creating an image file of C: drive for each node. In case something happens with Windows configuration or system corruption, I got a backup.

I know that I can generate database backups with RMAN and I am creating them. My question is about this scenario (which I haven't tested yet):

Suposse that my ASM filesystem get corrupted, but my Windows Servers 2008 are OK. Instances on Windows won't load because they won't find any database. In that case, how should I proceed to recover my database?
- Reinstall from scratch ASM filesystem? Should I create disk group with its original name?
- Restore RMAN backup to a new ASM filesystem? Is there any online manual about this specific point?

Any further comments about this will be very much appreciated.
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Top Expert 2009

Commented:
It depends on the scenario. There are 2 major scenarios that I can think of.

1) Your ASM instance is still ok, and scans/mounts the ASM disks and disk groups just fine.

In that case, you'd simply need to restore an RMAN backup of the data instances to the original ASM disks (after fixing whatever problem it was).

2) Your ASM instance is not ok, disks are not even mountable.

Resolve the root cause.
Get your ASM instance functional again. Assuming you have your init file backed up, just get your ASM instance restarted.

Then restore your other Oracle instance(s) with RMAN to their original paths.


So the common theme is:  You have to get the disks back to their original paths, ideally, before running RMAN to restore.

Does that help?
Top Expert 2009
Commented:
And for this reason, I don't store my RMAN FRA in ASM. I'd prefer to have it on a standard filesystem, either locally mounted or on NAS or NFS. When things blow up, you want your FRA to be easily accessible, without depending on ASM.

Author

Commented:
If I understand correctly your assumption number 2:

> 2) Your ASM instance is not ok, disks are not even mountable.
> Resolve the root cause
What if there's no solution and we have to reinstall again ASM filesystem?

> Get your ASM instance functional again.
I should reinstall again ASM filesystem and then create again diskgroup, groupnumber and paths with original names. I'd need to find a manual or procedure to do this.

> Assuming you have your init file backed up, just get your ASM instance restarted.
I should have my init file and control file backed up.
Then copy both files to ASM instance and start restoring from RMAN.

Author

Commented:
My RMAN files and archivelogs are not in ASM instance, so I suppose I follow your last recommendation.
Top Expert 2009
Commented:
>> I'd need to find a manual or procedure to do this.

It is the same procedure as the initial installation. Just make sure you can follow the same steps (same paths, same disk group names, etc.)

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