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Re: single node RAC system?

From: DA Morgan <>
Date: Thu, 07 Jun 2007 17:38:39 -0700
Message-ID: <>

herta wrote:

> On Jun 1, 3:00 am, DA Morgan <> wrote:
>> herta wrote:
>>> On Jun 1, 12:52 am, DA Morgan <> wrote:
>>>> herta wrote:

>>>>> On May 29, 5:39 pm, DA Morgan <> wrote:
>>>>>> herta wrote:
>>>>>>> On May 26, 2:25 am, DA Morgan <> 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 asinglesystem at the DRS.
>>>>>>>>> Thesinglesystem 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 assinglenodecluster, so
>>>>>>>>> that we can easily add instances if necessary.
>>>>>>>>> I tried installing clusterware on asinglenode, 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, ASM).
>>>>>>>>> It also warns that "this configuration is not certified or supported
>>>>>>>>> by Oracle Support Services".
>>>>>>>>> Has anyone tried setting up asinglenodecluster?  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 twonode
>>>>>>>>> cluster, and then take onenodedown.  How would that differ from a
>>>>>>>>> singlenodecluster 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-nodecluster and then shut down one machine.
>>>>>>>> Suggestions that you use VMWare will result in an unsupported environment.
>>>>>>>> --
>>>>>>>> Daniel A. Morgan
>>>>>>>> University of Washington
>>>>>>>> (replace x with u to respond)
>>>>>>>> Puget Sound Oracle Users
>>>>>>> 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 tosingleinstance but want the
>>>>>> ability to quickly turn thatsingleinstance into a cluster by
>>>>>> adding nodes.
>>>>>> --
>>>>>> Daniel A. Morgan
>>>>>> University of Washington
>>>>>> (replace x with u to respond)
>>>>>> Puget Sound Oracle Users

>>>>> Yes, I know I can set up a 2-nodecluster, and then remove onenode.
>>>>> 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 onenode.
>>>>> 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 asinglenodecluster in Oracle 9i
>>>>> without having to start from a twonodecluster.
>>>>> 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 asinglenodecluster, and the 'CRS-1006:
>>>>> No more members to consider' error has me worried that even when I'd
>>>>> start with a twonodecluster and remove onenode, the onenodewon'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
>>>> I'm a bit confused by what is confusing you.
>>>> A two-nodeRAC cluster is a special case. A cluster, to allow for
>>>> rolling upgrades, should be three or more nodes.
>>>> --
>>>> Daniel A. Morgan
>>>> University of Washington
>>>> (replace x with u to respond)
>>>> Puget Sound Oracle Users
>>> Hi Daniel,
>>> I'm not even worried about rolling upgrades at this stage.  Though I
>>> didn't know that you couldn't do a rolling upgrade on a two-node
>>> cluster.  We just moved our production and non-production environments
>>> to two-nodeclusters, so this definitely is relevant info for us.  Do
>>> you remember where you read about this?  (If not, I'll hunt around
>>> myself, but I'm rather pressed for time right now.)
>> It isn't that you can't do a rolling upgrade. Rather that when you
>> offline onenode... you lose TAF, lose FCF, lose load balancing,
>> lose that which makes RAC RAC. You no longer have a cluster.
>>> About the initial issue: when I try to install asinglenodecluster,
>>> the error I get suggests that the installation script is looking for a
>>> secondnode,
>> Which is why I suggested creating a twonodecluster and burning the
>> secondnodeto the ground as soon as you were finished or doing a
>> shutdown immediate so it isn't live.
>> --
>> Daniel A. Morgan
>> University of Washington
>> (replace x with u to respond)
>> Puget Sound Oracle Users
> Ran another cleanup procedure, rebooted the system for good measure,
> and now the installations runs fine.
> I guess the reboot must have cleaned up something that wasn't obvious
> to me.
> Thanks for telling me about the config you did at your client's,
> Daniel.  It's what really convinced me to try again.
> Thanks to all who posted and mailed suggestions.
> Only problem now is getting the listener to work, but I have the same
> issue in a dual node RAC.  Cf.
> Fwiiw, Oracle support have finally reported back today.  They confirm
> that a single node RAC is a supported configuration.
> Kind regards,
> Herta

Look at the listener.ora file in Morgan's Library at under RAC. It may help.

Daniel A. Morgan
University of Washington (replace x with u to respond)
Puget Sound Oracle Users Group
Received on Thu Jun 07 2007 - 19:38:39 CDT

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