10 Replies Latest reply on Jun 30, 2012 10:33 AM by Osama_Mustafa

    RAC interconnect and crossover

    alex p
      Let assume that we have only 2 nodes in oracle cluster.
      What is better for interconnect:
      Crossover or network with switch and why?

      Thank you.

      ps. we have dispute with 2nd DBA.
        • 1. Re: RAC interconnect and crossover
          Ganadeva
          using switch allows the reliability to be dependent on separate piece of network hardware rather than relying on the os and its underlying server hardware only. this includes taking care of any non-uniform approach for different os to make itself visible during reboots as well.
          regards
          1 person found this helpful
          • 2. Re: RAC interconnect and crossover
            alex p
            What about speed for interconnect? Is crossover faster? (Shorter cable, no switch between 2 servers)
            • 3. Re: RAC interconnect and crossover
              helter_skelter
              network with switch
              because:
              - crossover is not supported
              - switch provide the electrical isolation (without this isolation, NIC hardware errors on
              one of the servers could also cause hardware errors on the other server)

              cheers
              1 person found this helpful
              • 4. Re: RAC interconnect and crossover
                677160
                Hi,

                2 Nodes

                crossover cables with network redundancy or IP bonding

                Low Implementation/maintanance cost.


                2+n nodes

                Only Switch can be used.

                You should configure Isoleted network that is seperate two or more nodes from public network.
                1 person found this helpful
                • 5. Re: RAC interconnect and crossover
                  Ganadeva
                  One more consideration to the Oracle officially unsupported nature of such an arrangement causing later service issues is also the possibility to have a stable config with switch in place for a rapid ramp up in number of nodes.
                  regards
                  1 person found this helpful
                  • 6. Re: RAC interconnect and crossover
                    Markus.Michalewicz-Oracle
                    Hi Alex, all,

                    sorry, but I find this discussion dangerous, since missleading. Please, let me make it very clear:

                    If you plan to set up a production system, Oracle will not support crossover cables!

                    Therefore, regardless of whether or not a crossover cable is technically possible, it has no advantage over a switch. For test systems you may want to use anything that you want. However, please, note that a test system with a crossover cable cannot be a test environment for interconnect failure tests.

                    The reason is that Oracle has found that a lot of the interconnect failure tests will perform totally differently when using a switch - the network guys on this forum may want to elaborate why. In addition, Oracle has seen issues with crossover cables even under normal circumstances (no physical failure). While those were mostly based on auto speed negotiation of the NICs on both sides when using a crossover cable or other OS settings that need to be optimized, the behaviour was more predictable and stable using a switch.

                    Concluding, you would need to use a switch on your interconnect.

                    Thanks,
                    Markus
                    • 7. Re: RAC interconnect and crossover
                      557280
                      Starting with Oracle Database 10g, crossover cable is not supported
                      in a RAC configuration.Oracle Also recommend Network with high speed switch.

                      Regard's

                      Awanish
                      • 8. Re: RAC interconnect and crossover
                        helter_skelter
                        user554277 wrote:
                        Starting with Oracle Database 10g, crossover cable is not supported
                        in a RAC configuration.Oracle Also recommend Network with high speed switch.
                        Have You write something that was not written before ?
                        • 9. Re: RAC interconnect and crossover
                          AnandKumar
                          Hi All,

                          I am just restarting this thread, as this is my exact requirement.

                          We are in a process of installing/implementing a RAC 11gr2, and we are having delays in getting the switch for interconnect. My question is, can i install RAC with crossover cables, temporarily and once the switch and cables are ready in a day or two, can i introduce the switch.

                          Please help.

                          Thanks,
                          Anand.
                          • 10. Re: RAC interconnect and crossover
                            Osama_Mustafa
                            network with switch for sure , since crossover not supported .