Earlier this week, news leaked that Windows 8 has Hyper-V 3.0 built in. Leaked build 7989 shows it in the Windows Features section, and apparently it comes with enhancements to Hyper-V that will be exciting to see for both the client and server worlds. It seems there's also a new virtual hard drive format (.vhdx) that allows for up to 16TB of data, as opposed to the 2TB limit of .vhd. In addition, four cores are supported, as are hardware acceleration and a host of other items -- kudos to Robert McLaws for taking the screenshots and posting them for our benefit on his blog.
My first thought: Will there be a change in how Hyper-V works? Hyper-V currently requires a full OS install for a parent partition, then you install the separate child VMs. The child VMs are directly accessed through the Hyper-V hypervisor, but that extra OS install has to be there first, which takes up resources. On a server, this isn't a big deal because you can use the parent as the Hyper-V manager and such (but not much else). However, on a client PC, that extra OS could be an issue.
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Fortunately, the rumors indicate that Hyper-V 3.0 will not require a full copy of the Windows OS run as the parent. Instead, the much-discussed but never-seen MinWin will be the subset OS that sits between the hypervisor and the OS. This would include the OS kernel, the hardware abstraction layer (HAL), the file system, and support for networking. Some claim the footprint is small even for MinWin, requiring 25MB of disk space and 40MB of RAM to operate.
Hyper-V in Windows 8 could have three revolutionary benefits
Some Windows admins may have a hard time seeing the value of Windows 8 embedding Hyper-V beyond the "hey, that's cool" side. In fact, this is revolutionary for desktop admins in three areas:
- With Windows 7, you have to run a Virtual PC (called XP Mode) to run XP legacy apps. With Hyper-V in the picture, you could run XP, Vista, Windows 7, and even Linux apps (for supported Linux OSes) in the same environment -- and perhaps even Windows Phone apps.
- One possible scenario is where technologies such as App-V (which is used for application virtualization) and MED-V (Microsoft Enterprise Desktop Virtualization) would combine with Hyper-V 3.0 to provide server-based application delivery and VM management. This would, in turn, allow a safe blending of personal and business apps -- and even of VM "pools" -- for home users, office users, and bring-your-own-PC users alike, as well as increase security by decreasing malware's ability to hop applications.
- Third-party PC management tools could take advantage of Hyper-V client systems for easier deployment, update, and repair of PCs. One example of this would be Virtual Computer's NxTop product that uses a Xen-based hypervisor (NxTop Engine) for client deployment and management. Such a tool could easily be made hypervisor-agnostic, so it could manage the Hyper-V client and any other hypervisor-based client, though it seems as if VMware has put its plans for a client-side hypervisor on hold indefinitely.
It's the last area that has me incredibly excited. Companies like Virtual Computer have already made their mark on the world; thanks to their efforts, the deployment of the OS is a snap because it is image-based. You can deploy systems and patch them via one-to-many operations. Microsoft's approach for patch management is one-to-one, which is much more work. With Hyper-V in the desktop, Windows 8 could be managed many-to-one, with Microsoft and/or third-party tools.