Future of Sun Cluster
Could attend a presentation of the Sun Cluster team and the features that are coming soon. Lot of people were there because everyone wants to know if / when / how Sun Cluster will take advantage of the new S10 features. No timeframe officially given for each release. Educated guess sometimes available 
Besides the two next updates of SC3.1 and the future of Sun Cluster ( 3.2 ? ), note the appearance of a new product : Sun Cluster Geographic Edition.
Disclaimer : absolutely no commitment from Sun about the exact feature set and the timing at which the individual features will be released !
Sun Cluster 3.1 U4 ( Around september… )
- Support of Solaris 10
- Support of Oracle RAC on NAS storage from Network Appliance
- 8 nodes for Oracle RAC
- Support of Infiniband
- Live Upgrade
- Shared Interconnect with VLAN
- New data services : NFSv4, Siebel 7.7, Sybase 12.5, Oracle RAC on S10 for x86
Sun Cluster 3.1 U5
- Red Hat Linux support
- AMD64 support
- SMF integration
- ZFS as a failover FS
- EFI disk label support
- SNMP event MIB
- New data services : Some Linux agents
Future of Sun Cluster ( possibilities rather than facts )
- Service Level Mgt - Workload monitoring
- More S10 integration : local zones, SMF for data services
- Simplified command interface. Wizards.
- 16-node Oracle RAC
Long term objective : Full integration with other Cluster products, including Geographic edition and N1 provisioning products.
Relevant Links :
More info on Infiniband
Benefits of RAC on Sun Cluster