VMware vSphere 5.1 Enhanced vMotion
VMware has enhanced vMotion by combining traditional vMotion of a running virtual machine along with storage vMotion to create a "shared nothing" vMotion. This means you can vMotion a running VM from one physical host to another physical host without shared storage. Enhanced vMotion will count against the concurrent limitations of both vMotion and Storage vMotion. Today, one cannot perform more than 2 concurrent Storage vMotions per host. As a result, no more than 2 concurrent enhanced vMotions will be allowed. Enhanced vMotions are more expensive and thus that must be factored in when making migration decisions. Neither DRS and SDRS leverage Enhanced vMotion technology in 5.1.