we ran into oracle bug 3628715. without the fix oracle has troubles interpreting the multipathing devices.

so we have to install it on a volume via nfs, install the fix and reconfigure oracle to fcp.

:-/

--
Alexander Schalek, Technical Services / IT-Infrastruktur
Bacher Systems EDV GmbH
FN 54202i, Handelsgericht Wien
Clemens-Holzmeister-Strasse 4
A-1100 Wien, Business Park Vienna, Austria
phone: +43 (1) 60 126-34 | fax: +43 (1) 60 126-4
e-mail: as@bacher.at | web: www.bacher.at

From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Alexander Schalek
Sent: Monday, November 05, 2007 5:21 PM
To: Matthew Zito; toasters@mathworks.com
Subject: AW: accessing lun as a raw device using dm-multipathing from a rhel host

It looks like we are running into an oracle bug and this is not related to the o_direct flag.

Im not installing it myself, this is done by a oracle expert, and I don’t have the exact error code yet….hopefully tomorrow.

But they found a bug regarding rac installation on emc which shows similar problems during rac installation.

So it looks like this is an oracle/rhel issue…

Anyway, thanks for your explanation about o_direct ;-)

alex

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Von: Matthew Zito [mailto:mzito@gridapp.com]
Gesendet: Montag, 05. November 2007 17:08
An: Alexander Schalek; toasters@mathworks.com
Betreff: RE: accessing lun as a raw device using dm-multipathing from a rhel host

If you're in RHEL4, you just point your voting, OCR, etc. at the relevant /dev/mapper/mpath0, etc. device, and Oracle uses the O_DIRECT flag when it opens the device.  What is the error you're getting?

Matt

--
Matthew Zito
Chief Scientist
GridApp Systems
P: 646-452-4090
mzito@gridapp.com
http://www.gridapp.com

---

From: owner-toasters@mathworks.com on behalf of Alexander Schalek
Sent: Mon 11/5/2007 10:02 AM
To: toasters@mathworks.com
Subject: accessing lun as a raw device using dm-multipathing from a rhel host

Hi!

I have some troubles with a oracle rac installation on netapp fcp luns.

We use rhel4 u5 with dm-multipathing with a 2.6 kernel

Currently we have 4 partitioned and multipathed luns maped to the hosts(mpath0-3) but the rac installation exits with an error.

I found the following lines in the fcp host utilities setup guide:

Accessing LUNs using dm-multipath

Accessing LUNs as a raw devices

Overview

Instead of creating a file system, you can access a LUN as a raw device.

Be sure to use the /dev/mapper/ device created by dm-multipath to access the raw

device.

For the Linux 2.6 kernel used by RHEL 4, do not use the raw interface. Instead

open the device using the open call with the O_DIRECT flag.

*****

So I have to access the devices using the open call with the O_DIRECT flag!?

Can anyone of you guys explain this sentence to me?

How do I do that?

Many thanks and best regards,

Alexander