We have a Solaris RAC cluster running 10gR2 clusterware as well as Oracle RAC DB 10.2.0.5.0. We are migrating to 11gR2 for both the clusterware and RAC DB. We plan on using the DBUA for the DB RAC portion of the upgrade. However, as a 'fallback,' we also are going to have the manual upgrade steps for the RAC DB available as well. Have been perusing MOS looking for good reference material on how to perform a manual DB RAC upgrade. I have the Manual Upgrade Steps as well from the document "Oracle® Database Upgrade Guide 11g Release 2 (11.2) Part Number E23633-07" dated SEPT 2012. If anyone can think of any additional references and/or tips other than this, please feel free to respond. Thank you.
I can't help you with references but perhaps with experience.
My experience leads me to take a different approach. I would build a parallel 11gR2 RAC cluster, test it, patch it, and then move the datafiles over using DataPump Transportable Tablespaces.
The benefits are:
1. Less downtime
2. The ability to thoroughly test the 11g infrastructure prior to go-live
3. The ability to stay where you are in 10g if anything goes wrong and try again later