Re: OCFS is as fast as raw?

Don't know for sure, but I'll bet that OCFS doesn't bother with a buffer cache and simply performs direct I/O, just like raw devices. Besides better performance for databases, it also eliminates the need for cache coherency mechanisms like the innards of RAC.

Sometimes the simplest explanation is best...

on 9/18/03 3:25 PM, Jesse, Rich at Rich.Jesse_at_qtiworld.com wrote:

> After perusing the OOW'03 presentations, I see that Win Coekaerts'
> presentation says "IO throughput [on OCFS] is equivalent to RAW IO". Has
> anyone seen this behavior? It's entirely possible (probable!) that I didn't
> do something correctly, given the bastardization I needed to do (installed
> on RH9 because AS2.1 won't support our hardware), but I saw OCFS performance
> about 40-50 times slower than RAW (rough estimate).
>
> I didn't implement the OCFS fileutils as I wasn't going to manually do
> anything with the files. Surely the oracle binary doesn't call dd, cp, and
> mv directly for it's file management and data I/O, does it? Is it the
> "comm_voting=1" in the /etc/ocfs.conf file? Or is it more likely to be
> async IO (my guess)? Or a combo?
>
> Anyone with experience on this? Anyone attend Mr C's presentation?
>
> Thanks,
> Rich
>
> Rich Jesse System/Database Administrator
> rjesse_at_qtiworld.com Quad/Tech Inc, Sussex, WI USA

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