Re: RAC and Data Guard Configuration Question

From: Martin Klier <>
Date: Wed, 07 May 2008 12:20:44 +0200
Message-ID: <>

Hi Chris,

Chris Dunscombe schrieb:
> On the DR site we only have 3 nodes, we'd like 6 but 3 is all that we're going
> to get.
> The question is should we configure DR to have 1 instance per node (same as
> production) but this leaves only a total of 3 instances and hence 3 redundant
> UNDO tablespaces etc or have 2 instances per node?
> Also is it best practice to have the instance names on DR the same as in
> production.
> Any experiences, advice, "best practice" etc. for this is most welcome.

please keep in mind, that the standby database will only use one instance for recovery, so you can use the power of the RAC on standby side after a switchover only. In usual cases this should not be a problem, physical standby recovery is rather cheap.

You don't need to count instances the way you explained - a RAC recovery works very good on a single-instance standby system as well. Given, it has enough power, of course.

Since the physical standby database is only in MOUNT state, the undo tablespace usage does not count.

I assumed physical standby database as desired by you, should you prefer logical stb, things are changing greatly: But in this case, I won't use more instances per node than the production has.

Martin Klier

Usn's IT Blog for Linux, Oracle, Asterisk

Received on Wed May 07 2008 - 05:20:44 CDT

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