Yes you can! However you need to install Grid Infrastructure (GI) in cluster on both nodes, then install database software. Either during software installation or after that, DBCA would allow you to create 1) Single instance, 2) RAC database, 3) RAC One Node database. Keep in mind that RAC One Node is an option (additional license) to the Enterprise Edition of Oracle Database.
I've talked on that topic at the Bulgarian Oracle Users Group at 2011, here is the link to the presentation, you may find it useful. I might upload the videos as well if you need to have something like a proof of concept of just for your own:
Also I would go with one disk group for both databases, as long as they share the same physical disks I don't see the point of doing that ? Having one diskgroup would allow you to utilize better you disk/space resources.
The procedure would be:
1. Install GI in cluster.
2. Install software libraries.
3. Patch up to 18.104.22.168.
4. Create RAC One Node database using either command line or using Custom Template of DBCA.
At the end of the day, if you have standard edition license you can still install GI in cluster and create single instance databases on each server. The downside of doing that is that you need to manually failover the database to remaining node in case of disaster.
Thank you for the information, we will check about the licence
Today I installed a Test enviroment, like the production enviroment: 2 Rac Nodes 22.214.171.124 with one database
Then I installed one database Rac One Node with DBCA, but know I not able to find the utilities for Omotion. I find that for 126.96.36.199 there is a patch, but I am not able to find the patch for 188.8.131.52
do you know the number of the patch ?
Well, there is not utility omotion, they just call the technology for planned failover like that. To command RAC One Node you need to use srvctl utility. Documentation is good starting point:
Patches could be obtained from MOS (My Oracle Support), here are the numbers:
Patch 10404530: 184.108.40.206.0 PATCH SET FOR ORACLE DATABASE SERVER
Patch 13390677: 220.127.116.11.0 PATCH SET FOR ORACLE DATABASE SERVER