I get asked this all the time….and here is my answer. Microsoft’s virtual hard disk format, VHDX, has some important advantages over the legacy VHD format, as this VHD vs. VHDX comparison shows.
The release of Windows Server 2012 brought many new virtualization improvements, but one that caught the eye of many IT pros was the introduction of the VHDX file format. Windows Server 2012 supports the new format but also lets Hyper-V administrators use the legacy VHD format. With two virtual hard disk formats to choose from, let’s take a minute to talk about VHD vs. VHDX.
To start the journey, one needs a foundation to start. I assume everyone knows what a hypervisor is, but if you don’t check out Wikipedia.
VMware has been the leader for a number of years, along with another vendor and open source, like Xen and KVM. Microsoft also has a hand in Virtualization early on in the with Virtual Server, which was originally developed by Connectix, but no real traction and frankly it sucked..