3 Replies Latest reply: Aug 21, 2012 8:26 PM by damorgan RSS

    RAC One Node versus Clusterware Single Instance Failover?

    801904
      (cross posted from RAC Forum since question applies to both technologies equally)

      Hello everyone

      I am trying to design a database consolidation high-availability cluster for Oracle 11g R2 64-bit Enterprise Edition (X86-64) on Oracle Linux 6.x UEK, using Oracle 11.2.0.3 (the latest as of Aug 2012).

      We don't need RAC Multi-Node now or in forseeable future because none of the databases we run break the capacity of a single node.
      Likewise, we don't need to use Oracle VM to virtualise the database instances.

      We plan to use SGA and PGA memory management to run multiple instances on same hardware operating on a single Linux 64-bit O/S image.

      Does it sound ok so far?

      Two or three of 4-socket, 40-core Intel 64-bit servers with 512GB of RAM each (relatively cheap at today's HW commodity prices) will be sufficient to run all Oracle databases we have on Linux 64-bit.

      So the two HA options that I know of are:

      (1) use Oracle Clusterware/Grid/ASM to provide for instance failover
      (2) use Oracle RAC One Node on top of Clusterware/Grid/ASM

      As I understand it RAC One Node is significantly more expensive than the "free" Oracle Clusterware/ASM/Grid (since we own Oracle 11.2.0.3 Enterprise Licences already).

      So why should my employer pay for RAC One Node licence given they already own Single Instance Fail-Over and Restart protection from Clusterware/Grid/ASM ?

      I also read that Data Guard 11.2 may not be supported with RAC One Node on 11.2? True?

      Will same Data Guard 11.2 work with a Single-Instance Failover running on Clusterware/Grid/ASM ?

      Who is running RAC One Node? Why?
      Who is running Single Instance Failover with Clusterware? Why?
      Who is using Data Guard with either of the above?

      Please share your stories.

      Many thanks
      Yuri B
        • 1. Re: RAC One Node versus Clusterware Single Instance Failover?
          Balazs Papp
          So why should my employer pay for RAC One Node licence given they already own Single Instance Fail-Over and Restart protection from Clusterware/Grid/ASM ?
          thats up to you (company policy, service level agreement) to consider the extra features provided by it:
          http://www.oracle.com/technetwork/products/clustering/overview/ds-rac-one-node-11gr2-185089.pdf?ssSourceSiteId=ocomen

          you can perform online relocation and patching, which you cant with a simple clusterware active/passive failover
          plus its a tested solution that works "off-the-shelf"
          I also read that Data Guard 11.2 may not be supported with RAC One Node on 11.2? True?
          Supported starting with 11.2.0.2. (Not in 11.2.0.1)
          Will same Data Guard 11.2 work with a Single-Instance Failover running on Clusterware/Grid/ASM ?
          Yes.
          Who is running RAC One Node? Why?
          Who is running Single Instance Failover with Clusterware? Why?
          Several of our customers use the latter and none the former. From their point of view, RAC One Node features doesnt worth that much extra license price.
          Some use Oracle Clusterware, while others use the cluster service provided by the platform/OS with custom scripts.
          Who is using Data Guard with either of the above?
          The customers who also need DR on top of HA. Its nothing special to be honest.
          • 2. Re: RAC One Node versus Clusterware Single Instance Failover?
            801904
            thanks.

            Today I spoke to our Oracle representative who also pointed out that only RAC One Node will give us Active/Active, the Clusterware solution will only give us Active/Passive.

            This means that if I wanted to run 50% of our databases on Node A and the other 50% on Node B then I must use RAC One Node to run all databases on same Linux cluster.

            To run 50% on Node A in Active/Passive Clusterware I would need to run two Active/Passive clusters, i.e. have Node A1 and Node A2 being Active/Passive for first 50% of databases and a further Node B1 and Node B2 to run Active/Passive for the second 50% of the databases. Node A2 and B2 would be Passive, used for fail-over. Node A1 and B1 would be active. I would need to buy 4 servers.

            If I were to choose RAC One Node then I could run a 2-Node or 3-Node single Linux Cluster in Active/Active/Passive configuration, saving at least 1 hardware node per data centre (i.e. at least 2 nodes saved in total).

            Now I need to compare the pros and cons of either option as Active/Passive Oracle Clusteware appears to be more widely used solution (being older) than relatively new RAC One Node option and Active/Passive Clusterware may therefore be more stable/robust than RAC One Node?

            Thanks!
            • 3. Re: RAC One Node versus Clusterware Single Instance Failover?
              damorgan
              What you just wrote is completely totally incorrect. Well that an physically impossible too.

              If your Oracle sales rep told you this please have them contact me directly.