Long-distance vSphere vMotion migration requires that the latency between sites is less than 150 ms. VMware also recommends that a bandwidth of 250 Mbps be available for each vSphere vMotion operation. For configurations where the respective vCenter Server instances are in separate SSO domains, migration must be implemented leveraging the VMware vSphere API. An example of how to use PowerShell to execute API-driven long-distance vSphere vMotion operations can be found here.