As stated inside the Sun Cluster 3.3 releases notes, this version adds support for Oracle 11g Release 2. Although, there is some case where upgrade to 3.3 is harder than only patching existing 3.2 installation.
Here it is!, looking at the changelog of the following patches, they add support for 11gR2 to the Sun Cluster 3.2 release:
Sparc
- 144221-01 - 126047-15
X86
- 144222-01 - 126048-15
Oracle’s new release could then be clusterized without upgrading to 3.3. Notes that it is although recommended to go on with Solaris 10 Update 9 for new Oracle releases.