Oracle Scratchpad

October 3, 2011

Personal RAC

Filed under: Oracle,RAC — Jonathan Lewis @ 12:55 pm BST Oct 3,2011

Thanks to Tim Hall, I can now show you a snapshot of OEM demonstrating my personal four-node RAC.

As I pointed out in a comment to the previous post I had got four instances up and running, but the install of the DB control software had failed on two of them. Tim suggested that I simply try recreating the repository on all four nodes (which might normally be considered drastic, but I didn’t have a working system, and I hadn’t done any customisation, so why not …). He pointed me at an article of his on trouble-shooting Enterprise Manager, and pointed out that I’d need to add the “-cluster” option. So I got the cluster and instances up and running (20 minutes to start it all up), and issued a single command:

emca -config dbcontrol db -repos recreate -cluster

Then I sat back and waited.
Twenty-five minutes later I had db control running on all four nodes, and I used Internet Explorer from the host machine to get the snapshot above.

Of course, now that I can do it, I probably won’t ever feel the need to do it again. I can’t get all four nodes running while my documentation VM (which is a Windows XP Pro) is running, so I’ll probably only run a maximum of three nodes at any one time, and often limit it to two. But it’s nice to know that I can do it if I really want to, and sometimes four nodes are necessary.

A couple more things that were causing me trouble which I’ve now fixed:

  • I couldn’t get OEM from my documenation VM to talk to the RAC VMs – but it all worked properly (though slowly)  after the re-install of the repository.
  • I couldn’t get Samba to open Windows directories on the host (Windows 7) from the RAC VMs, though I could get to the other Windows VMs (XP Pro) with no problem  – but mount -t cifs does what I really needed to do.


  1. You might be able to get 4 nodes running much more smoothly by releasing the memory which is locked by ocssd, cssdmonitor and cssdagent. This script will do it… — or stop by the (IOUG RAC SIG) RAC Attack table at UKOUG and we’ll get it running in no time. I have successfully setup an cluster with 760MB of memory on each node. (However I think 1GB is a bit more comfortable; at 760, the kernel swap daemon occasionally starts fighting with clusterware before the script releases the memory.)

    Comment by Jeremy Schneider — October 3, 2011 @ 1:27 pm BST Oct 3,2011 | Reply

    • Jeremy,

      Thanks for that suggestion – I’ll be giving it a try.
      I still have a number of things to do to get to my “production” level. Taking out memory_target is one of them (currently 750MB), and seeing what happens if I switch to huge pages.
      I’ve probably installed lots more bits than I really need as well – all the X-windows stuff is probably running daemons everywhere, and all I want to do typically is putty into a node.

      Comment by Jonathan Lewis — October 4, 2011 @ 3:19 pm BST Oct 4,2011 | Reply

  2. Hi Jonathan ,

    I would like to recommend to use Vbox instead of VMware

    Comment by liumaclean — October 3, 2011 @ 3:06 pm BST Oct 3,2011 | Reply

    • Liu,

      I did think about it – I’ve seen notes that it’s a much smaller install. However I have a legacy system to deal with; I’ve been using a VMWare copy of my last laptop but one for a couple of years and I didn’t want to risk breaking it by switching from VMWare to OVM. I’m very risk averse when it comes to the things I have to use all day every day.

      I gather from Tim Hall, though, that he’s been successful installing both OVM and VMWare on the same machine – so long as he doesn’t try an use both environments simultaneously.

      Comment by Jonathan Lewis — October 4, 2011 @ 3:22 pm BST Oct 4,2011 | Reply

  3. I tried VBOX and had loads of issues. Others may have had success. But Iv tried maybe 20-30 installs of RAC across VMBox and VMware .. found VMware the best. There are a few ways of releasing up memory. Jonathan, Ive managed to have 3 RAC nodes going, reasonably well, on an 8G Win 7 Pro. So, with that extra 8G you have there, Im sure you can probably use comments like Jeremy’s and google searches to get that memory you are using down. Similar to Jeremy above, I ended up running each VM on 810M. So – it seems two of us have got under that 1G mark and working “ok”.
    I too had problems with OEM like you had. I will have to see if I can get it working with the fix you detail. Thanks for that.

    Comment by kent — October 4, 2011 @ 12:53 pm BST Oct 4,2011 | Reply

    • I meant to add “your first RAC ‘categorised post'” .. a whole new era for your Jonathan ;o)

      Comment by kent — October 4, 2011 @ 1:03 pm BST Oct 4,2011 | Reply

      • Kent,

        Now that it’s so easy to run the system up – and especially since it’s now portable and suits my travel pattern – it’s possible that I’ll fell inclined to build more RAC demonstrations for the blog; mind you, there are about 75 drafts of other things still awaiting completion first.

        Comment by Jonathan Lewis — October 4, 2011 @ 3:31 pm BST Oct 4,2011 | Reply

  4. You can download an Oracle VM template for 11.2 RAC from here: It’s quicker & easier to get a cluster going this way, compared with vbox or vmware. You can even use it for a production build.

    Comment by RD — October 4, 2011 @ 12:56 pm BST Oct 4,2011 | Reply

    • But then you dont learn as much … I feel it useful to have to go through the pain in order to understand it more. Unless you are just a developer that is

      Comment by kent — October 4, 2011 @ 1:04 pm BST Oct 4,2011 | Reply

      • Totally depends on your purpose. Do you want to learn how the installer works, or how the software behaves once it’s installed? “Going through the pain” may be a waste of your time if there’s an easier way to get to your desired end point.

        Comment by RD — October 4, 2011 @ 1:09 pm BST Oct 4,2011 | Reply

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