Re: Storage choice for Oracle database on VMware

Thank you all for the valuable input!

> what is the problem with direct I/O? You should never run an Oracle
database through page cache anyway :)

I'm not sure if direct I/O is always the best choice. I think that certain workloads may benefit from the FS cache.

Anyway, I'm wondering why setall is still not the default value for filesystemio_options on Linux (most probably because of the bugs with certain filesystems and kernel versions).

Regards
Dimitre

Il giorno mar 30 ott 2018, 22:38 Andrew Kerber <andrew.kerber_at_gmail.com> ha scritto:

> Most places with growing databases and heavy duty environments on vmware
> use ASM. Some use XFS or similar and LVM, though I am not fond of those.
>
> On Tue, Oct 30, 2018 at 4:34 PM Leng <lkaing_at_gmail.com> wrote:
>
>> 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
>> > --
>> > http://www.freelists.org/webpage/oracle-l
>> >
>> >
>> --
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>>
>>
>>
>
> --
> Andrew W. Kerber
>
> 'If at first you dont succeed, dont take up skydiving.'
>

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