Re: ASM and disk partitions offset
- From: Niall Litchfield <niall.litchfield@xxxxxxxxx>
- To: "Radoulov, Dimitre" <cichomitiko@xxxxxxxxx>
- Date: Thu, 16 Feb 2012 22:30:00 +0000
So the good news is : they're doing the right thing.
The bad news :- you're now an I/O expert and all I/O issues belong to you.
Cynical? Moi?
Niall
On Thu, Feb 16, 2012 at 6:58 PM, Radoulov, Dimitre <cichomitiko@xxxxxxxxx>wrote:
>
> A quick follow-up on this:
> we requested again from the storage team and the HW vendor to double check
> if partition sector alignment was "appropriate",
> this time (after having called their experts ...) they confirmed that it
> would be better to partition the disks using a different offset
> for the first sector (128 instead of the default - 63 in this case).
>
> So thanks again Niall,
> now I'm reading the articles you mentioned.
>
>
>
> Best regards
> Dimitre
>
> On Thu, Feb 16, 2012 at 11:34 AM, Niall Litchfield
> <niall.litchfield@xxxxxxxxx> wrote:
>
> Dimitre,
>>
>> "I wouldn't bother" is probably incorrect. The details will depend on the
>> array stripe size, the sector sizes and probably the specific hardware.
>> That
>> said most vendors recommend the 1mb starting point for a partition
>> because
>> it has as a common divisor most of the usual allocation unit sizes and
>> disk
>> label sizes. I quite like this article
>> http://blogs.msdn.com/b/**jimmymay/archive/2009/05/08/**
>> disk-partition-alignment-**sector-alignment-make-the-**
>> case-with-this-template.aspx<http://blogs.msdn.com/b/jimmymay/archive/2009/05/08/disk-partition-alignment-sector-alignment-make-the-case-with-this-template.aspx>
>> written from a windows perspective with SQL in mind, but really the basic
>> issue isn't software specific. FWIW Oracle, Microsoft and VMWare all
>> recommend that you align your storage hardware with the FS/Volume
>> manager so
>> as to avoid doing multiple IO requests where a single request would do,
>> references below.
>>
>>
>> http://www.vmware.com/pdf/**Perf_Best_Practices_vSphere4.**0.pdf<http://www.vmware.com/pdf/Perf_Best_Practices_vSphere4.0.pdf>
>> http://www.oracle.com/**technetwork/articles/systems-**
>> hardware-architecture/lun-**alignment-163801.pdf<http://www.oracle.com/technetwork/articles/systems-hardware-architecture/lun-alignment-163801.pdf>
>>
>> http://support.microsoft.com/**kb/929491<http://support.microsoft.com/kb/929491>
>>
>
>
>
--
Niall Litchfield
Oracle DBA
http://www.orawin.info
--
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