Re: Storage choice for Oracle database on VMware

Asm is great when you plan correctly. If you don’t it’s very painful. Eg. If you have different sized disks asm will be forever rebalancing, and failing as there is not enough space on the odd disk. So you need to vacate the diskgroup to rebuild it. (Yes, you know... not my fault, the previous consultant did it...) If there’s an asm bug you may have to take an outage on the Asm to apply the patch.

Normal disk operations like dd to asm is almost impossible. Trying to find that corrupted data block on the asm disk takes great asm expertise from a great oracle support engineer.

Those were some up of my worst asm nightmares. It was only 2 years ago. I have since moved on...

Cheers,
Leng

> On 31 Oct 2018, at 7:20 am, Stefan Koehler <contact_at_soocs.de> wrote:
>
> Hello Dimitre,
> what is the problem with direct I/O? You should never run an Oracle database through page cache anyway :)
>
> I would go with tweaked XFS (e.g. "nobarrier" as this information is usually not passed through correctly with VMDKs on VMFS, etc.) if it is just one single instance in this VM.
>
> Best Regards
> Stefan Koehler
>
> Independent Oracle performance consultant and researcher
> Website: http://www.soocs.de
> Twitter: _at_OracleSK
>

>> "Radoulov, Dimitre" <cichomitiko_at_gmail.com> hat am 30. Oktober 2018 um 19:12 geschrieben: 
>> 
>> Thank you Chris, Matthew and Niall, 
>>  
>> so the question is if performancewise ASM is worth it. 
>>  
>> With the default Oracle database settings the I/O on XFS would be synchronous, right? 
>>  
>> And if I understand correctly Note 1987437.1, on Linux you cannot enable async I/O without turning on direct I/O too.
>>  
>> Regards 
>> Dimitre

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