Re: Redo block size...

From: Holger Baer <holger.baer_at_science-computing.de>
Date: Fri, 16 Jan 2004 13:51:35 +0100
Message-ID: <bu8moo$7e7$1@news.BelWue.DE>

Noons wrote:
> Holger Baer <holger.baer_at_science-computing.de> wrote in message news:<bu62bf$qpm$1_at_news.BelWue.DE>...
>
>

>>>What filesystem would you recommend for the datafiles/redos on Linux RH? I've heard that
>>>both, ext2 and ext3 are suitable.
>>>

>
>

>>according to this link, ext3 it is:
>>
>>http://www.quest-pipelines.com/newsletter-v2/linux2.htm

>
>
> <careful>
> According to that link, you can NOT derive that any of the file
> systems detailed there are better for redo.
>
> The benchmarks do NOT discriminate between database datafiles
> (using a large block size typically >4K) and redo logfiles
> using MUCH SMALLER block sizes.
>
> The results on that link assume that all writes in Oracle are of
> the same db block size. Nothing could be more wrong.
>
>

>>And in the Oracle on Linux-Course, Oracle recommends using of ext3.

>
>
> That's my gut feel too, but it's only that: a feel.
> Based on it being similar to ext2 plus having journaling
> (which prevents fsck problems at boot time). Debatable.
>
> The link above has done nothing to confirm or deny which f/s
> is better for redo.
> </careful>
>

Thanks for your corrections. When I first read that article, I was just overwhelmed how especially the raw files and jfs subperformed and that probably got me carried away ;-)

However, I felt a small correction to Marcin's plain ext2 is faster was called for; as usual it all depends.

As a side note: My personal feeling is that since ext3 is the default filesystem for RH AS 2.1 (again, according to the Oracle course notes), Oracle just recommends what is the default anyway, and the mentioned link at least shows that it doesn't necessarily kill performance...

But to know what is best, the OP will have to test for him self, I'll admit.

Cheers,

Holger Received on Fri Jan 16 2004 - 06:51:35 CST