Re: Do we need multiple REDOLOG member if it is already on SAN box?

From: Noons <>
Date: Mon, 2 May 2011 01:20:38 -0700 (PDT)
Message-ID: <>

On Apr 30, 4:33 am, charles <> wrote:

> I have a question.  I have a Oracle database, everything is
> on SAN storage ( Raid 10). When i am asking for another LUN for 2nd
> redolog members, he told me we have already mirrored for u at the san
> level.  So he thinks it is not necessary to have two members of
> redolog in each group.
> Could somebody share some idea with me?

Been discussed many times. Recently at the oracle-l list the consensus even from the Oakies is do not do mirroring twice. Either do Oracle multiple members, or do SAN-based mirroring. Doing it twice achieves really nothing other than slowing things down. One or the other, not both.

Given that the days SANs lost data are long gone (not a single data failure in over 4 years now of 12TB of I/O per day) we've gone for SANbased  last year. Fine so far and archived redo logs copied to DR site every two hours gives me even more comfort.

YMMV based on how paranoid you are. Received on Mon May 02 2011 - 03:20:38 CDT

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