The setting in vSphere is a property of the ESX(i) host, found within the configuration tab in the Virtual Machine Startup/Shutdown options section. Fig. 1 shows how to set automatic startup for VMs on a host.
|Figure 1. A VM startup sequence can be set with timing for each host.
The properties section will allow the startup options to be configured. It is a good idea to shorten their startup time if the hosts power up and are ready to go