ext3 data=ordered - good enough for oracle?

[Herta Van den Eynde]

Thanks for your replies and pointers, Johann and Zach.  I hope to find 
time next week to study the extra information.

Kind regards,

Herta

Zach Brown wrote:
> Herta Van den Eynde wrote:
> 
>>Given that the default journaling mode of ext3 (i.e. ordered), does not
>>guarantee write ordering after a crash, is this journaling mode safe
>>enough to use for a database such as Oracle?
> 
> 
> Yes, the database doesn't rely the kind of functionality that
> data=journaled provides that data=ordered doesn't.  data=ordered is fine.
> 
> 
>>If so, how are out of sync writes delt with?
> 
> 
> The database, just like ext3/jbd, implements its own consistency
> mechanisms by careful write ordering.  ext3 uses in-kernel device APIs
> to issue writes and find out when they're on disk, the database ideally
> uses O_DIRECT.
> 
> I looked around otn.oracle.com to find a doc that talks about
> configuring and verifying AIO+O_DIRECT in the database but got tired of
> searching.  You might be able to find something if you're more patient
> than I was.
> 
> - z
> 

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