Re: Oracle memory allocation on Linux 2.6

From: <>
Date: Fri, 4 Apr 2008 23:41:38 -0700 (PDT)
Message-ID: <>

On 3 avr, 10:28, Mladen Gogala <> wrote:

> On Wed, 02 Apr 2008 03:20:27 -0700, vitalisman wrote:
> > On 9i, filesystemio_options=none (default) and Oracle binaries are not
> > linked for AIO (default, at least with RAC). I'm in the process of
> > testing AIO and DIO on RAC 9i following Oracle support questions, but
> > the first attempts gave way to some instance internal errors... I've
> > asked the support if this is really a supported configuration (at least
> > with OCFS1, it was not, apparently.)

> > Thanks Mladen for your answer!

> Jerome, direct I/O should lower memory consumption simply because it
> bypasses buffer cache over which we have no control.

I know how DIO should work, but my first tests with OCFS2 did not evidence any OS cache bypassing. Have you ever enabled DIO with OCFS2? Did that work?

> - min_free_kbytes,
> - dirty_background_ratio,
> - dirty_expire_centisecs
> - dirty_writeback_centisecs.

> You cannot control the size of cache components (like buffer cache) but
> you can control behavior and overall limit with min_free_kbytes.

Those are parameters I usually check/tune on Linux.

Thanks again for your answer. Received on Sat Apr 05 2008 - 01:41:38 CDT

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