Re: Redo block size...

joel-garry_at_home.com (Joel Garry) wrote in message news:<91884734.0401161304.6b769838_at_posting.google.com>...
> Holger Baer <holger.baer_at_science-computing.de> wrote in message news:<bu8moo$7e7$1_at_news.BelWue.DE>...
> > Noons wrote:
> > > Holger Baer <holger.baer_at_science-computing.de> wrote in message news:<bu62bf$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
>
> Slightly OT but interesting: http://kerneltrap.org/node/view/715
>
> Maybe we can come up with a similar benchmark test using redo.
>
> jg

Joel,

Thanks, that thread was very interesting. I wonder what OSDL has come up with in this area.

http://www.osdl.org/cgi-bin/eidetic.cgi?command=display&modulename=projects&query=completed_projects

there is a linux test project:
http://sourceforge.net/projects/ltp/

I used to get "Open" magazine, guess I didn't renew that subscription. LinuxWorldExpo is coming up soon in nyc, Oracle may have some reference systems there on display.

Pd

easy oracle-specific would be
SQL> @catpatch.sql; (9.2.0.4) Received on Sat Jan 17 2004 - 10:44:51 CST