Even I fell prey to the excitement before realizing their limitations the hard way. I'm referring to Hyper-V Generation 2 virtual machines (VMs), new in Windows Server 2012 R2. As their name suggests, Generation 2 VMs are a wholesale evolution to the structure and delivery of VMs on Microsoft's signature hypervisor.
They arrive with a long list of new features, many of which are patently exciting. New things such as boot from SCSI-attached storage, installation of guest OSes through synthetic network cards (which come in handy for Windows Deployment Services [WDS] and Microsoft Deployment Toolkit [MDT] deployments), a secure boot feature and larger boot volume, online boot disk expansion and add/remove of DVD drives. Generation 2 VMs also consume fewer host resources thanks to their elimination of device emulation. That indirectly translates into a better performing VM.
Most important, Generation 2 VMs boot faster -- ridiculously faster than their equivalent Generation 1 VMs. This feature alone is sure to excite IT pros who're perpetually worried about downtime metrics, and absolutely tired of waiting for black screens to turn gray.