Appendix G: Upgrade Checklists : Phase 4
   
Phase 4
Additional Upgrades
Upgrade all hosts that are connected to datastores and vSphere Distributed Switches.
Upgrade VMFS Datastores to VMFS-5.
Upgrade vSphere Distributed Switches.
Modify provider virtual datacenters to support virtual hardware version 8, if desired.
Modify organization virtual datacenters to enable fast provisioning, if desired.