Enterprises look to virtualization for more than just consolidation of servers and applications. They look for high availability of mission critical applications and automated migration when failures occur in the hardware or software as well. VMware ESX Server 3.5 provides some additional high availability capabilities, but still has a way to go.

The VMware High Availability component (included in VMware Infrastructure 3 Enterprise) offers basic monitoring and fail-over capabilities for ESX Server host failures. This is accomplished by having an agent on the server send out heartbeats to a monitoring system. When a server failure is detected all of the virtual machines (VMs) on that physical server are restarted on available systems. While this provides a level of protection on the physical server side it does not help when individual VMs or applications fail.