What are you trying to achieve?

What is your pain point for downtime.

VMotion is not a HA solution. It lets you migrate VMs between hosts while they are running.

VMWare has 3 HA solutions.

1) HA. Where 2 or more hosts share a SAN unit. If a host goes physically down, the VMs running on it crash, and they are automatically assigned to a new host and powered up. Cheap, efficient if you can afford the downtime.

2) FT. Somewhat similar to MS clustering services. Tere ae some pretty brutal limitations on the make up of the VMs to qualify for FT. But no downtime.

Both of those are geared towards the failure of equipment within a physical location.

3) SRM. Needs replication capable SANS, Fast connection between remote sites and $$$$. It will automate recovery in the event of a site being destroyed.