Re: How to convert RAC database to single Instance Database

  • From: Tim Gorman <tim@xxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 30 Aug 2004 17:59:34 -0600

Qaiser,

Did you contact Support, or Sales, for that answer?  :-)

Admittedly, running non-RAC on a Veritas clustered file-system is unusual
(i.e. falls into the "why would you do this?" department), but I can't see
why it can't be supported.  Except for all the bells and whistles and
complications and overhead of a clustered file-system, it's just a
file-system, right?

You'll need to get rid of all but the first of your threads of redo.  An
"ALTER DATABASE DROP LOGFILE THREAD" command should help here.  Just don't
drop thread #1, please.

Optionally, you might also want to get rid all but one of your UNDO
tablespaces (or all but one of your RBS tablespaces if
UNDO_MANAGEMENT=MANUAL), though you don't have to do this.  It's just a good
idea to reclaim some space.

Then, you'll want to get rid of the RAC layer of code by relinking without
it.  Someone else might want to help here (as I don't have a RAC system
handy), but the make script for linking the executables should have a RAC or
no-RAC flag somewhere.

Finally, make sure that the parameter CLUSTER_DATABASE defaults to FALSE in
your remaining database instance.

I don't know if the OUI will allow the deinstall of the RAC option (which is
probably what the support person was talking about), but you could just
reinstall everything without it, I suppose.  Although, if the OUI keeps
detecting "/dev/odm" then it will just keep reinstalling RAC.  So, you might
have to ask Veritas how to de-install the cluster, which will probably yield
the same answer as from Oracle... :-)  Or move the database to a
non-clustered server...

Oh, did I say to back everything up (i.e. database and ORACLE_BASE) before
you start this?  I meant to...

Hope this helps...

-Tim

P.S.    When all this is done, do you get to pocket the license fees that
        Oracle returns?  I'm going to expect a cut...



on 8/30/04 5:31 PM, Q A I S E R at qrasheed@xxxxxxxxx wrote:

> - 9.2.0.5 64bit
> - RAC
> - Solaris 8
> - VERITAS DBE?AC 3.5
> 
> Does anybody on the list has any experience converting a RAC database
> to a single instance Database in Cluster File System configuration?
> 
> I was able to find a Doc. on metalink with step by step instructions
> on "How to convert a single instance Database to RAC", but not the
> other way round. So, I raised a TAR for this. The analyst's response
> from Oracle is "We cannot convert a RAC database into a Single
> instance database, that is the reason why you didnt find any steps. It
> is not supported".
> 
> It does not makes any sense that you cannot convert from RAC to
> non-RAC environment, unless Oracle does not want their customers to go
> away from RAC !. I would think that you could set
> cluster_database=false, and bring up the database in single instance.
> Get rid of the extra threads and undo tablespaces. Has anybody on the
> list done something like that?
> 
> Qaiser

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