8 Replies Latest reply: Jul 1, 2014 3:00 PM by Levi Pereira RSS

    Oracle RAC Extended

    Neo-b

      Hello All,

       

      I am currently having Oracle RAC 11gR2 2 nodes with ASM. This is my primary site.

       

      I am studying the option to implement Oracle RAC extended on a 2nd site. in which my design will be Oracle RAC extended with 2 nodes on primary site and 2 nodes on secondary site.

       

      Should I re-implement the current Oracle RAC on my primary site to support RAC extended? in case i am using Oracle RAC extended with ASM ? or with VPLEX?

       

       

      Regards,

        • 1. Re: Oracle RAC Extended
          Salman Qureshi

          Hello,

           

          You certainly need to redesign your RAC to have it extended. You need to have storage accessible in remote side, private interchangeability and several other things. Theoretically it is just like adding a new node (on remote site) to the RAC to make it extended RAC, but actually it is not this much simple.

          Following white paper should help you understand the extended RAC,

           

          http://www.oracle.com/technetwork/products/clustering/overview/extendedracversion11-435972.pdf

           

          Salman

          • 2. Re: Oracle RAC Extended
            Hemant K Chitale

            You are going from 2 nodes to 2+2 nodes.  What will be the usage of the 2 nodes at the secondary site ?

            Have you considered and rejected DataGuard as a failover option ?

             

             

            Hemant K Chitale

            • 3. Re: Oracle RAC Extended
              Neo-b

              Yes I considered Dataguard,

               

              I am studying all my High availability options and one of them is Extended RAC. so i am checking its advantage and disadvantages.

               

              Regards,

              • 4. Re: Oracle RAC Extended
                BPeaslandDBA

                How far away is the second site?

                 

                If this is for HA, then normally the cost of a low latency, high speed network between the sites is enough to eliminate Extended RAC from consideration. Also, you will have to add in the cost of the shared storage in two locations. All of this screams "hardware $$$$". Whereas Data Guard doesn't have these high costs.

                 

                 

                Cheers,
                Brian

                • 5. Re: Oracle RAC Extended
                  Levi Pereira

                  My recommendation, don't think "Which options I have", but think "What are my needs".

                   

                  For example:

                  Did you need 0 downtime? If yes, you can need RAC Extended and Dataguard. Both have different purposes protecting against different types of failures.

                   

                  Based on your needs choose better option.

                  From point of view Administration and Maintenance of  environment Dataguard has less cons compared with Extended RAC.

                  • 6. Re: Oracle RAC Extended
                    Neo-b

                    Is there any restriction on the distance between the primary site and the secondary site that Oracle DataGuard can afford?

                     

                    Regards,

                    • 7. Re: Oracle RAC Extended
                      BPeaslandDBA

                      Oracle's recommendation for Extended RAC is to be less than 100km apart. With Data Guard, you can be on the other side of the world, literally. The farther away, the hard it is for a zero data loss solution though.

                       

                      Cheers,
                      Brian

                      • 8. Re: Oracle RAC Extended
                        Levi Pereira

                        There is no physical limit to the distance between primary and standby sites, there is a practical limit to the distance that can be supported.

                        As distance increases, the amount of time that the primary must wait to receive standby acknowledgement also increases, directly impacting application response time and throughput.