Just a quick blog entry. I have installed 11g RAC quite a few times already and just wanted to share with you folks an observation.
Those of you who have installed 10gR2 Clusterware (CRS) know that towards the end of the CRS installation you have to go from node to node and execute $ORA_CRS_HOME/root.sh. When you run it on the last node the script will try to set up VIPs (this is why you have to run the CRS root.sh as root in an xterm because it is a window-less JAVA app). Oracle1gR2 has had an annoying bug in it that failed the VIP setup because it was very picky about the IP addresses you assigned to VIPs. The workaround for that was to ignore the problem and then invoke $ORA_CRS_HOME/bin/vipca and walk through the setup of VIPs (including GSD and so on). It was a minor problem that was easy to work around.
10g and 11g Clusterware Co-Existence
I have not seen that problem with 11g. In fact, the reason I’m blogging this is because I just walked through an install of 10gR2 Clusterware on my cluster running x86 RHEL4 attached to NAS (NFS). I need a setup where I have both 10g and 11g clusterware installed and I need to be able to “hide” and “expose” either with a few simple commands to test one or the other. After the successful install of 10gR2 CRS, I “hid it” (to include all the residue in /etc) and proceeded to install 11g CRS. Since I just did both 10gR2 CRS and 11g CRS installs back to back I was reminded that 10gR2 CRS has that pesky problem and I did have to hand-invoke vipca to get through it. I was pleasantly reminded, however, that 11g does not have that problem.
For those of you who are used to seeing the complaint about VIPs at the conclusion of the last root.sh execution, see the following screen shot from 11g and breathe a sigh of relief.
And a picture speaks a thousand words so here is a shot of my little 11g NAS RAC clusterware setup:
Note to self: Investigate whether 11g CRS works with 10gR2 RAC instances and make a blog entry. It should, so I will.
Kevin Closson's Blog: Platforms, Databases and Storage 
I’m actually curious. I do know it was just released but from all your tests, what is your opinion of 11g RAC? For companies wanting to start testing Oracle RAC and deploy it in the next 6 months, would you recommend trying it on 11g or sticking with the already old but well tested/matured 10gR2?
Kevin,
I’m glad Oracle fixed this silly issue in 11g.
Can you publish the procedure you used for hiding one CRS so you can install another on the same system?
Also, did you try mix-n-match of CRS 11g and DB 10g or vice versa? I think that at least the first variation is theoretically supported.
Hello prodlife, how’s that NFS situation going?
As for your questions, I’ll try to document multiple resident clusterware ASAP, but first I’m looking into running 10g RAC under 11g clusterware.
dfuentes,
Aside from all the natural application-compat testing, I’d say 11g. Remember, however, I am not, nor do I claim to be a production DBA. If you are building a bespoke app, why not get unto a release that at least has Oracle’s attention. Oracle10g is considered Legacy. That is both a good thing and a bad thing as I’m sure you know.
Hi,
Iam happy to see the description given by you on 11g RAC. Iam setting up 11g RAC on OEL4.5 64-bit with EMC clarrion. It would be great having input from you. I have installed and worked on 10gR2 on OEL4.5,RHEL4.5.
Regards
Nagaraju T
Hi,
I installed 11gR1 Clusterware on NODE1 and NODE2 successfully.
When i try to run installer for 10.2.0.1 to install just ORACLE HOME, it is not detecting the CRS which is up and running and not installing 10G ORACLE HOME as rac ready.
Please suggest.
Thanks
Neeraj Kataria
@Neeraj
I’m running into the same Problem, set ORA_CRS_HOME to the path of he 11g clusterware home and the 10R2 Installer will over the rac installation.