Re: single node RAC system?

On May 29, 5:39 pm, DA Morgan <damor..._at_psoug.org> wrote:
> herta wrote:
> > On May 26, 2:25 am, DA Morgan <damor..._at_psoug.org> wrote:
> >> herta wrote:
> >>> We are currently setting up our disaster recovery site (DRS).
> >>> For Oracle, we want to use Dataguard to copy our databases to physical
> >>> standby databases on a single system at the DRS.
> >>> The single system is quite capable of running the Dataguard load, but
> >>> should we need to run production at the DSR, it will not suffice. We
> >>> would therefore like to set up this system as single node cluster, so
> >>> that we can easily add instances if necessary.
> >>> I tried installing clusterware on a single node, but the start of ONS
> >>> fails with:
> >>> Start of `ora.l27.ons` on member `l27` failed.
> >>> CRS-1006: No more members to consider
> >>> CRS-0215: Could not start resource 'ora.l27.ons'.
> >>> Metalink article 2411114.1 suggests that the set up is possible,
> >>> though the environment described there differs from ours (we use
> >>> 64-bit SLES 10, Oracle RAC 10.2.0.3, ASM).
> >>> It also warns that "this configuration is not certified or supported
> >>> by Oracle Support Services".
> >>> Has anyone tried setting up a single node cluster? If so, did you get
> >>> the ONS error? How did you work around it?
> >>> As to the support status, in theory, we could set up a two node
> >>> cluster, and then take one node down. How would that differ from a
> >>> single node cluster configuration?
> >>> Alternative suggestions to achieve our goals are also welcome, of
> >>> course.
> >>> FWIIW, I opened an SR with Oracle four days ago, but they have yet to
> >>> respond with something other than "we're looking into it'. A previous
> >>> posting in ORACLE_DBA_EXPERTS also remained unanswered.
> >>> I'm sort of pressed for time as the goal is to ship this to the DRS in
> >>> three
> >>> weeks time, and just getting a first copy of the physical databases on
> >>> the storage is going to take a while.
> >>> Kind regards,
> >>> Herta
> >> Build a two-node cluster and then shut down one machine.
>
> >> Suggestions that you use VMWare will result in an unsupported environment.
> >> --
> >> Daniel A. Morgan
> >> University of Washington
> >> damor..._at_x.washington.edu
> >> (replace x with u to respond)
> >> Puget Sound Oracle Users Groupwww.psoug.org
>
> > Thanks, Daniel. We're considering this, using a test system as our
> > second member, but we're wondering what impact this would have when
> > we'd need to upgrade the software. (We cannot ship the test system to
> > the DR site.) Has anyone actually done this?
>
> > Kind regards,
>
> > Herta
>
> We just got done doing this for a public company where they are
> doing Data Guard from RAC cluster to single instance but want the
> ability to quickly turn that single instance into a cluster by
> adding nodes.
> --
> Daniel A. Morgan
> University of Washington
> damor..._at_x.washington.edu
> (replace x with u to respond)
> Puget Sound Oracle Users Groupwww.psoug.org

Yes, I know I can set up a 2-node cluster, and then remove one node. I took the Oracle RAC course, and removing a system from the cluster and adding another one was the last exercise of the training.

I'm just worried about how we can upgrade that one node. As explained, we want to run Dataguard standby databases on this system, and as you may know, Dataguard requires the primary and standby databases to run the same software versions. I would hate not being able to install a critical patch in production just because it cannot be installed on our DR system.

Oracle has documented setting up a single node cluster in Oracle 9i without having to start from a two node cluster. My colleague read some Oracle 10g beta documentation with a similar setup, but the official documentation does not mention it anymore. I tried in vain to install a single node cluster, and the 'CRS-1006: No more members to consider' error has me worried that even when I'd start with a two node cluster and remove one node, the one node won't be upgradeable because it lacks other cluster members.

Given the changes between 9i and 10g, I am reluctant to follow that path without confirmation from Oracle that they will support this configuration.
(Still no word from them after 10 days, though. :-( )

Kind regards,

Herta Received on Thu May 31 2007 - 17:32:19 CDT