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Re: EMC stuff

From: Henry Poras <henry_at_itasoftware.com>
Date: Fri, 26 Aug 2005 02:06:19 -0400
Message-ID: <430EB15B.5030103@itasoftware.com>


I gave this a bit more thought and realized I was being rather thick. Of course you should be able to share an array to multiple nodes. If, as EMC states, 'cluster software' is necessary to share a LUN without Access Logix, then for Oracle, this must mean OCFS. For 10g, the shared CRS files (registry and voting) must be either on raw or OCFS. To the best of my understanding, a clustered file system is installed solely on the servers, the SAN knows nothing about it. If so, and this is necessary for a shared LUN, why not RAW?? If the SAN doesn't know, the SAN doesn't know.

Rephrasing my questions to EMC support, I was told that there is no hardware limitation. EMC claims the restriction because they want to prevent their users from corrupting their data. Without Access Logix or some outside software, there is nothing to prevent corruption. Of course that is what RAC is there for.

Henry

Henry Poras wrote:

> Thanks for all the offline emails. According to the document "EMC
> Clariion Configuration Planning Guide" (published 2005)
>
> "Storage systems for any hared installation require EMC Access Logix
> software to control server access to the storage system LUNs.
>
> "The shared-or-clustered direct installation can be either shared
> (that is, use Access Logix to control LUN access) or clustered
> (without Access Logix, but with operating system cluster software
> controlling LUN access)."
>
> So the way I read this, RAC on Clariion needs either Access Logix or OCFS.
>
> Henry
>
>
> -----Original Message-----
> *From:* oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org] *On Behalf Of *Henry Poras
> *Sent:* Monday, August 22, 2005 2:36 PM
> *To:* oracle-l_at_freelists.org
> *Subject:* EMC stuff
>
> We are beginning to do a RAC install with a Clariion SAN for
> storage. One thing I was told doesn't sound right to me, but since
> I don't pretend to be an EMC expert (and don't play one on TV.
> Heck, I barely get passed the 60's reruns on TV and EMC wasn't
> even around then) I am having trouble confirming or denying.
> Supposedly a LUN can only advertise itself to a single entity
> (i.e. node, cluster). This makes the RAC install kind of
> difficult. I always thought of a SAN as shared storage. What is
> shared storage if a LUN can't be accessed by multiple nodes?
> Anyone have any idea what the source of the confusion is?
>
> Thanks.
>
> Henry
>

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Received on Fri Aug 26 2005 - 01:09:32 CDT

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