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Changing disk paths in RAC & ASM [message #560525] Fri, 13 July 2012 19:17 Go to next message
gwatts
Messages: 2
Registered: July 2012
Location: UK
Junior Member
Hi,

Need some advise. We are about to undertake a storage migration of our RAC environemnt from EMC to XIV storage.

The migration method we are using means that we will be presented with identical disks post the migration, however the UNIX paths to the disk devices will be changing. Using our migration method it is not possible to present the old and new devices at the same time.

Therefore once the migration is complete i need to update the device configuration to reflect the new paths

I believe this is done using the following techniques but I am unsure as some of the documentation is ambiguous and I have not done this before

Changing path to Voting Disks
crsctl add css votedisk <new_path_to_disk> -force
crsctl delete css votedisk <old_path_to_disk> -force

Changing path to OCR Disks
ocrconfig repair ocr <new_path_to_ocr>
ocrconfig repair ocrmirror <new_path_to_ocrmirror>

Changing paths to ASM disks
alter system set asm_diskstring='<new_device_path>' scope=both;

Any advise on the above greatly appreciated - I appreciate there are other steps (such as ensuring correct permissions on device files and making sure cluster services stopped) - but just wanted opinion on high level process

[EDITED by LF: removed superfluous empty lines]

[Updated on: Sat, 14 July 2012 09:08] by Moderator

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Re: Changing disk paths in RAC & ASM [message #560540 is a reply to message #560525] Sat, 14 July 2012 01:27 Go to previous messageGo to next message
John Watson
Messages: 4403
Registered: January 2010
Location: Global Village
Senior Member
Quote:
but just wanted opinion on high level process
You have forgotten to restore the vote disk and OCR.
A much better option would be to create a new 11.2 cluster, and restore your 10g databases onto it.
Re: Changing disk paths in RAC & ASM [message #560551 is a reply to message #560540] Sat, 14 July 2012 05:20 Go to previous messageGo to next message
gwatts
Messages: 2
Registered: July 2012
Location: UK
Junior Member
Hi John,

Thanks for taking the time to reply.

Whilst we were planning to take a backup of OCR and voting disk - I did not think this would be required to be restored ?

Following the storage migration the servers will be presented with like for like (byte for byte) disks at the point when we shutdown - the only difference being that the disks now have different paths.

Therefore I was hoping we would be able to get by with just updating the voting and ocr location using the commands I mentioned (ocrconfig repair ocr and crsctl add css votedisk ). Can you clarify why we would still need to restore ?

Like you say best option would be to build new cluster - unfortunately not an option in this scenario.

Thanks again for your time

Graham

Re: Changing disk paths in RAC & ASM [message #560554 is a reply to message #560551] Sat, 14 July 2012 07:55 Go to previous message
John Watson
Messages: 4403
Registered: January 2010
Location: Global Village
Senior Member
I don't understand. If you have new discs, you no longer have vote files or OCR. You can't just re-create them (well, you can, but that is a non-trivial task) you have to restore. I think your technique can function only if original and new devices are concurrently visible.

And btw, I think you may need to up date your ocr.loc file before doing anything.

But really, you have to update your clusterware. You will get virtually no support for 10.2, it is seriously unstable compared to the current release, and you will never have a better opportunity to upgrade. I cannot imagine a business case for not doing it.

Good luck (you might need it!) with whatever method you decide upon.
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