Hi Riyaj, Thanks for your input. "Not that extended cluster is bad, but needs lot more thinking, application code changes, configuration issues etc." I did not understand how there will be application code changes when using extended RAC, To my understanding there are some considerations to be taken at design part and there are some configurations involved. Could you please let me know any issue you foresee specific to extended RAC cluster ? Thank You, Kind Regards, Sreejith Nair From: Riyaj Shamsudeen <riyaj.shamsudeen@xxxxxxxxx> To: Sreejith.Sreekantan@xxxxxxxxxx Cc: Andrew Kerber <andrew.kerber@xxxxxxxxx>, oracle-l@xxxxxxxxxxxxx, rshamsud@xxxxxxxxx Date: 11/15/2010 11:33 PM Subject: Re: Question on Oracle 11G RAC 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> 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 DISCLAIMER: "The information in this e-mail and any attachment is intended only for the person to whom it is addressed and may contain confidential and/or privileged material. If you have received this e-mail in error, kindly contact the sender and destroy all copies of the original communication. IBS makes no warranty, express or implied, nor guarantees the accuracy, adequacy or completeness of the information contained in this email or any attachment and is not liable for any errors, defects, omissions, viruses or for resultant loss or damage, if any, direct or indirect." -- Andrew W. Kerber 'If at first you dont succeed, dont take up skydiving.' 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