This setting can be changed on the fly with no impact to the host.  This setting (currently) only controls the behavior of the array during things like upgrades and outages - it doesn't affect anything related to the normal operation of the array. What's more, as of version 4.0.2 both the "ESX" and "Other" settings result in the same behavior - although that will likely change in a future version as we tweak it a little for ESX.  So yes, you can change it any time, without any need to do anything on the host. The host will not even detect the change in any way.
Hello, We have XtremIO hosting all ESXi hosts and the initiator type is configured as "other" instead of "ESX". Is it safe to change the initiator type to "ESX" when the host is online or doe we have to unmount the LUNs, take the host offline and then change the initiator type?  Thanks
Change Initiator type XtremIO