5 Replies Latest reply: Dec 10, 2012 2:49 AM by Billy~Verreynne RSS

    Hetrogenous RAC - is it possible ?

    Jimbo
      Is it possible to compose a RAC Cluster using nodes runing different OS's ( I suspect the answer is no ) but I want to tease out a couple scenarios

      I recall challenging Oracle on their Grid concept (I suppose really now replaced with their cloud concept ) which was lauded as being able to add in any spare servers to consolidate processing power. I then asked the question could you therefore combine a Windows Server with unix server in regards to the processor grid. In pure grid theory the answer should be yes but when pressed Oracle they admitted no.

      Q1. So I am guessing the same is true of RAC - I suspect you could not have one node as Windows and another node as unix ( the difference in the file path specification alone would surely scupper it ).

      Q2. What about a unix node and a linux node ?

      Q3. What about binary compatible nodes eg one node being RHEL and the other being OEL ?

      Q4. Finally what about 2 nodes that were the same OS but had a slight different version of ORACLE_HOME eg 11gR1 and 11gR2 ?

      any thoughts appreciated,
      Jim
        • 1. Re: Hetrogenous RAC - is it possible ?
          P.Forstmann
          It is not possible to have heterogenous OS RAC nodes. http://docs.oracle.com/cd/E11882_01/install.112/e24660/chklist.htm#BHACGCII says:

          >
          You must use the same operating system on each node in the cluster. In addition, Oracle strongly recommends that you use the same software configurations on each node of the cluster.
          >

          And it is also not possible to have Oracle DB 10.2 on one node and Oracle DB 11.2 on another node for the same cluster and for the same database.

          Edited by: P. Forstmann on 6 déc. 2012 12:19
          • 2. Re: Hetrogenous RAC - is it possible ?
            Jimbo
            thanks for the info - my suspicions confirmed !
            • 3. Re: Hetrogenous RAC - is it possible ?
              Billy~Verreynne
              Jimbo wrote:

              I recall challenging Oracle on their Grid concept (I suppose really now replaced with their cloud concept ) which was lauded as being able to add in any spare servers to consolidate processing power. I then asked the question could you therefore combine a Windows Server with unix server in regards to the processor grid. In pure grid theory the answer should be yes but when pressed Oracle they admitted no.
              RAC is not Cloud. Despite what the marketing suits may spin.
              Q3. What about binary compatible nodes eg one node being RHEL and the other being OEL ?
              Yes. In fact did this recently on a test cluster. Not a good idea though (obviously) as there can be some kernel driver issues (e.g. ADVM of 11.2.0.2 runs on 5.4 kernel and not on the 5.7 kernel). Also makes o/s management more complex. I'm a big believer that each and every server node in a Grid/RAC needs to be identical at o/s level. Same kernel version, same drivers, same rpm's, same +/etc+ configs (such as hosts, multipath, udev) and so on.
              Q4. Finally what about 2 nodes that were the same OS but had a slight different version of ORACLE_HOME eg 11gR1 and 11gR2 ?
              Well, you can have multiple Oracle Homes on the same server. So you should be able to have a 10 node Grid, policy managed RAC, server pool 1 running a 10gr2 RAC database as 5 instances, and server pool 2 running a 11gr2 RAC database as 5 instances. Offhand I do not see why this would not be possible.

              Some years ago (due to circumstances) I had another Oracle Home on node 1 of a 4 node RAC, running a standalone Oracle db instance on the RAC sever node that was running RAC db instance 1. (since has moved that to its own dedicated server). So I do not see why this 2nd Oracle Home could not run another RAC db version...
              any thoughts appreciated,
              Well, the obvious thought is why do you want to throw heterogeneous stuff together into an Oracle RAC? To achieve what need, and address which requirement, exactly?
              • 4. Re: Hetrogenous RAC - is it possible ?
                KODS
                Hi Jimbo,

                adding to "Billy Verreynne's" comments, in RAC the utlity CLUVFY is verifying the node equavalence before installing the cluster software.
                Even while adding the new node to the cluster, the pre-requisite is to run CLUVFY utility.
                • 5. Re: Hetrogenous RAC - is it possible ?
                  Billy~Verreynne
                  KODS wrote:

                  in RAC the utlity CLUVFY is verifying the node equavalence before installing the cluster software.
                  Even while adding the new node to the cluster, the pre-requisite is to run CLUVFY utility.
                  Correct - but these checks (like the same o/s kernel version for Linux) can be circumvented by setting env variable IGNORE_PREADDNODE_CHECKS to "N".