Re: Taking export from SECONDARY_INSTANCE from 02 node RAC

From: <shweta.kaparwan_at_googlemail.com>
Date: Thu, 26 Feb 2009 11:45:20 -0800 (PST)
Message-ID: <196f3a88-4d3a-4f37-aebf-e359dc52e71f_at_p11g2000yqe.googlegroups.com>



On Feb 26, 6:17 pm, sybra..._at_hccnet.nl wrote:
> On Thu, 26 Feb 2009 09:03:35 -0800 (PST),
>
>
>
>
>
> shweta.kapar..._at_googlemail.com wrote:
> >Hi All
>
> >We are at :
>
> >Oracle 9.2.0.6
> >HP Ux : 11.23
> >RAC : 02 Node
> >( say node-A & node-B)
>
> >Primary Instance is running in node-A & secondary instance running in
> >node-B.
>
> >All db connections goes to PRIMARY_INSTANCE , we control it via TNS.
> > Hence at a given time PRIMARY_INSTANCE running in host-A is Active
> >and SECONDARY_INSTANCE in host-B is UP but IDLE with respect to db
> >connections. i.e. no connections goes to host-B.
>
> >Now question:
>
> >I want to start the export backup database ( size 50 GB) from host-B
> >by connecting to SECONDARY_INSTANCE.
>
> >i.e. my "exp" connection/session  will be connecting to
> >SECONDARY_INSTANCE in host-B.
>
> >Whether this will cause " a ton of interconnect traffic all of a
> >sudden as many of the blocks will have to be shipped for the first
> >time to the other node".
>
> >In simple words , how good it would be to export via
> >SECONDARY_INSTANCE or are there any bad part of it in above scenario?
>
> >Many Thanks
>
> >Regards
>
> >Shweta
>
> It wouldn't matter as you are already greatly abusing RAC. If you
> don't use the second instance at all, you either don't need RAC, or
> you should configure RAC ClusterGuard I, which comes with RAC, and
> which is an active/passive configuration.
>
> Also when a block isn't found on whatever instance, it will query the
> other instance, no matter whether that instance is loaded or not.
>
> Importantly also a scattered read on 9iRAC for n blocks will result in
> n requests to the other node.
>
> I observed a factor 5 speed increase during exp/imp when I just
> cluster_database to false.
>
> So my advice is very simple:
> Either upgrade to something supported (10g will request the n blocks
> at a time) or dump RAC completely. You don't need it, and you are
> wasting your money, simply due to your ignorance.
>
> --
>
> Sybrand Bakker
> Senior Oracle DBA- Hide quoted text -
>
> - Show quoted text -

Many thanks Sybrand Bakker.

Actually due to application restriction we are not able to explot the real RAC. So we are using sort of Active-Passive mode of RAC.

 also could you please eloborate / guide me to some doc/ref for below point:
> Importantly also a scattered read on 9iRAC for n blocks will result in n requests to the other node.

Regards

Shweta Received on Thu Feb 26 2009 - 13:45:20 CST

Original text of this message