I have a Data center created in the vSphere client with 3 ESX host that are clustered. We have vSphere 5 Enterprise Plus license edition. All 3 ESX host are put in a cluster under a datacenter. They are all powered on. As it currently stands, HA, DRS and FT are not enabled. To enable both these options, do the ESX host need to be shut off? Or do we have to create a new cluster and redo all this again just to enable all those features.
Can you also give a brief explanation of what each one of those feature does (FT, DRS, and HA), and why we would want to enable them?