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Re: ZFS & Oracle

From: Remigiusz Sokolowski <>
Date: Tue, 25 Sep 2007 11:06:05 +0200
Message-id: <>

Joe Frohne wrote:
> Hello,
> I searched the archives for general ZFS information and found a few
> threads about ZFS and snapshots. These threads are about a year old.
> I am wondering if there is any general impression of running Oracle
> 10.2.x under ZFS today. Are people doing it successfully? What are
> the good, the bad and the ugly of running Oracle under ZFS?

here there is quite good article about ZFS in general in section Additional ZFS References You 'll find few sensible articles with focus on databases

we use ZFS for MySQL only so no experience with Oracle directly, but there are some similarities, when considering innodb in general recordsize of ZFS should be equal to db block size, redologs should be separated (though with MySQL we have no this enabled, but as long as performance is satisfactory, we do not change configuration) and with max recordsize (i.e.128k). There is not much more - one can tune few other things, but these are dependent on one's traffic, and sometimes do not mean much. And one more thing - use the last available version.
I think that somewhere in one of those articles I saw comparison to UFS (with direct IO) and that was ZFS performance=3/4 UFS performance, so UFS wins

And from personal experience - from time to time our host looses its visibility of ZFS resources. I am not too technical to explain why, and thought that we do not need to trouble it after last patches were added more than a half year ago, but now experience higher traffic and problems returned.
While such things hit us, I believe MySQL can loose some commited transactions - probably tx records are handed to the ZFS, while it is already in some instable state, confirmation is returned, while buffers do not persist physically on disk or something like that. Of course it can be problem inflicted by composition of our traffic, our hardware (x86 arch), our staying at some earlier version of ZFS and so on.



Remigiusz Sokolowski <>
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Received on Tue Sep 25 2007 - 04:06:05 CDT

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