Re: 10g RAC Install with Raw Devices

  • From: "Ghassan Salem" <salem.ghassan@xxxxxxxxx>
  • To: wjwagman@xxxxxxxxxxx
  • Date: Fri, 30 Mar 2007 21:30:47 +0200

William,
look at this on metalink (and search for
O_DIRECT)<https://metalink.oracle.com/metalink/plsql/f?p=130:14:5760572964337490118::::p14_database_id,p14_docid,p14_show_header,p14_show_help,p14_black_frame,p14_font:NOT,220970.1,1,1,1,helvetica>

On 3/29/07, William Wagman <wjwagman@xxxxxxxxxxx> wrote:

Alex,

Can you provide some pointers to further information on this subject.

Thanks.


Bill Wagman
Univ. of California at Davis
IET Campus Data Center
wjwagman@xxxxxxxxxxx
(530) 754-6208
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Alex Gorbachev
Sent: Wednesday, March 28, 2007 8:07 PM
To: naqimirza@xxxxxxxxx
Cc: tcarlson@xxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: 10g RAC Install with Raw Devices

Don't use raw devices if you are running Oracle 10.2.0.2 (or 3?) on
Linux.
* Raw devices are being kind of depreciated in Linux.
* Additional level of complexity (bind + permissions) so more likely to
fail.

The problem with block devices (/dev/sd*) is that IO to block devices
is buffered IO - going via OS cache. Unless you open them with
O_DIRECT flag. Starting with 10.1 (IIRC) Oracle adds this to datafile
open call (filesystemio_options must be at least directio?). With
10.2.0.1 the same is done for OCR - it's opened with O_DIRECT.
However, voting disks open call still have a bug so during
installation of 10.2.0.1 you will need to bind voting disks at least.
After upgrade to later patchset (I think 10.2.0.2 is enough but don't
remember - need to check list of bugs fixed), voting disk is also
opened with O_DIRECT.

On 3/28/07, Naqi Mirza <naqimirza@xxxxxxxxx> wrote:
>
> How did you setup the raw devices ? Did you bind raw partitions to
your raw
> devices. I'm not an expert on linux but I see you're specifying
/dev/sda2 -
> once bound shouldnt this be something like /dev/raw/raw1 ?
> I haven't had the installer complain about devices, but I have had
clufvy
> fail on the shared storage check - but that was specific to the hp-ux
> platform.

--
Best regards,
Alex Gorbachev

http://www.oracloid.com
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