Re: Question on Oracle 11G RAC
- From: Riyaj Shamsudeen <riyaj.shamsudeen@xxxxxxxxx>
- To: Sreejith.Sreekantan@xxxxxxxxxx
- Date: Mon, 15 Nov 2010 12:04:25 -0600
Sreejith
I think, what you are describing is a RAC extended cluster. You really
don't want to do this. Cache fusion locks (BL) will be requested if the
block is transferred between the instances, it doesn't matter one instance
is update only and another is read only etc. This configuration will cause
lot more issues then you are envisioning.
Not that extended cluster is bad, but needs lot more thinking, application
code changes, configuration issues etc.
As Andrew said, Active data guard with real time apply is the correct
solution is for this problem. Not RAC.
Cheers
Riyaj Shamsudeen
Principal DBA,
Ora!nternals - http://www.orainternals.com - Specialists in Performance,
Recovery and EBS11i
Blog: http://orainternals.wordpress.com
OakTable member http://www.oaktable.com
Co-author: "Expert Oracle practices: Oracle Database Administration from the
Oak Table" http://www.apress.com/book/view/9781430226680
On Tue, Nov 9, 2010 at 7:42 AM, Sreejith S Nair <
Sreejith.Sreekantan@xxxxxxxxxx> wrote:
> Hi, Thanks for the hint.
> I have a couple of questions.
>
> In a normal 2 node RAC database environment, will the two instances be
> always active ? I mean , will cache fusion takes place frequently , If my
> application and DMLs does not user parallelism ?
> I am just thinking , when will the high speed interconnect becomes busy
> with data transfer
>
>
> If I can create a service one each node and associate to instance , How
> does my client tnsnames.ora looks like ? I could not figure out this.
>
> Appreciate any help on this.
>
> Kind Regards,
> Sreejith Nair
>
>
>
>
> From: Andrew Kerber <andrew.kerber@xxxxxxxxx>
> To: Sreejith.Sreekantan@xxxxxxxxxx
> Cc: oracle-l@xxxxxxxxxxxxx
> Date: 11/09/2010 06:57 PM
> Subject: Re: Question on Oracle 11G RAC
> ------------------------------
>
>
>
> That approach would work, but in 11GR2 you can active dataguard with real
> time apply, which allows you to have the standby open in read only while the
> logs are being applied. That seems to be what you really want.
>
> On Tue, Nov 9, 2010 at 2:24 AM, Sreejith S Nair <*
> Sreejith.Sreekantan@xxxxxxxxxx* <Sreejith.Sreekantan@xxxxxxxxxx>> wrote:
> Hi friends,
>
> I have got this question from customer regarding Oracle 11G R2 RAC.
>
> The customer have stated a preference for configuring the Oracle RAC nodes
> so that, in a two node system, the first node bears all the update load,
> whereas the second RAC node would have connections that are read-only. The
> two nodes would still operate as failovers for one another. The reason for
> this , they stated was to reduce network traffic between the nodes to
> coordinate transactions and locking. They have asked for this configuration
> as 'one update node and one read-only node' / a primary update node and a
> secondary read-only node .
>
> We have thought about implementing this configuration for our two
> applications as follows
>
> Application features
>
> Application 1 - which performs regular updates,heavy transactions,long
> running reports et - schema 1
> Application 2 - performs smalled updates and small reads. - schema 2
>
> Application 1 can point to node 1 of this RAC and application 2 to node 2 (
> using node affinity ).When any of the node fails , the client connections
> will fail over to surviving node.
>
> I would like to get some recommendations on this approach from experts.
>
> 1) Do you think the above approach using node affinity is a good approach ,
> ie pinning one schema in one node with one database for a two instance(node)
> RAC ?
> 2) Any documents / reference to configure this approach in RAC ?
> 3) Is there any other way to achieve the requirement put by the customer ?
> 4) If the above said nodes are in two data centres, Will it be a
> recommended approach ? I think these two nodes should be in same data
> centre.
> 5) If we configure Load balancing ( in normal RAC or in the setup mentioned
> above) then that would take considerable network b/w ?
>
> OS is RHEL 5.4 on 64 bit.
>
> Please share your view on this.
>
> Thanks ,
> SSN
>
>
>
>
>
>
>
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> --
> Andrew W. Kerber
>
> 'If at first you dont succeed, dont take up skydiving.'
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