Re: RAC vote 11gR2 Question

From: Sanjay Mishra <>
Date: Sat, 28 Sep 2013 16:02:19 -0700 (PDT)
Message-ID: <>

Thanks Anjum and Dimitre.

 From: Maaz Anjum <> To:
Cc: Sanjay Mishra <>; "" <> Sent: Friday, September 27, 2013 12:12 PM Subject: Re: RAC vote 11gR2 Question  

Sanjay, I think the likelihood of a SAN failure is (in reality) quite low, and to reiterate Dimitre's point; striping ASM over multiple LUN's might be a futile effort because they "virtual disks" might be carved out of possibly several physical disks. The most severe case I have encountered was when an IBM manage storage array was "lost" due to mechanical errors. It took out the DATA diskgroup with it. The failure was so severe that we had to rebuild the database from a previous backup.

Just some food for thought: Would it be better to look at the OCR auto backups?


On Fri, Sep 27, 2013 at 10:48 AM, Radoulov, Dimitre <> wrote:

Hi again Sanjay,
>On 27/09/2013 15:58, Sanjay Mishra wrote:
>> Thanks Dimitre for the details. So does it means that having 4 Disks
>> of 512M in each failure group or One disk of 2G is same in this scenario.
>> e.g
>> Failure group 1==> 1disk of 2G or 1G vs 4 disk of 512M
>> Failure group 2==> 1disk of 2G or 1G vs 4 disk of 512M
>> Failure group 3==> 1disk of 2G or 1G vs 4 disk of 512M
>> Trying to understand if multiple disk in Filure group for OCRVote can
>> provide any additional benefits beside space.
>Well it depends if each disk is a physical disk(less likely) or LUN
>striped over multiple disks in RAID configuration (external storage,
>most likely the case).
>If the former is true - it makes sense to stripe the ASM extends over
>multiple physical drives for performance.
>If these are actually logical units that are already striped over
>multiple physical drives, me personaly, I don't see how it could be
>beneficial ...

A life yet to be lived... 
Received on Sun Sep 29 2013 - 01:02:19 CEST

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