Opting for Hyper-V in laptop-based virtualization

Running a Hyper-V virtual machine off a laptop is convenient but not without some drawbacks, such as the need for high-end hardware and compromised performance.

Running a virtual machine off a laptop with Microsoft Hyper-V gives users a "travel sized" hypervisor, if you will. But the convenience of a portable virtualization demo is not without drawbacks.

Getting virtualization products to work in an easy-to-travel form is a roller coaster of "It works today, but who knows about tomorrow." Not too long ago some enterprising individuals figured out how to reconfigure the 3.0 version of VMware's flagship ESX Server to work within VMware Workstation. With a little VMX hacking and some very specific settings, you quickly found yourself with a tidy package to take on the road.

But with the release of version 3.5, ESX's easy-to-transport capabilities came to an end. Updates to the functionality of its hypervisor meant that ESX servers could boot, but attempting to start a virtual machine quickly crashed the VM-in-a-VM. The fault: Newer chipsets are now required to make the newer software run again.

Creating a laptop-ready virtualization demo with Microsoft's Hyper-V involves a bit less preparation than with ESX. Due to Hyper-V sitting atop Microsoft Windows, there isn't the same need to create a hypervisor-in-a-hypervisor situation on your laptop. Upon installation, Hyper-V's primary partition immediately becomes the OS instance you use as your primary laptop instance.

But before you throw away your overpriced Vista OS for an even more expensive Windows Server 2008 instance, consider a few gotchas that you might see during the conversion:

Hyper-V requires high-end hardware. Many recently purchased laptops have the necessary hardware prerequisites to run Hyper-V. But if your laptop is older than a year or two, you might find yourself lacking. Hyper-V requires a 64-bit version of Windows Server 2008, which obviously requires an x64 processor. It also requires virtualization extensions (Intel VT or AMD-V) and support for the execute disable bit (Intel XD or AMD NX) on those same processors. Most importantly, with the potential for multiple OS instances running simultaneously, it's going to require a large amount of RAM. Four gigabytes is an absolute must. If you're lacking any of these, you'll need a hardware upgrade before ever installing any software.

Windows Server 2008 isn't Windows Vista. Although Server 2008 and Vista share the same code base, each is its own operating system. One would think that device drivers designed for Windows Vista x64 should work with Windows Server 2008 x64, but universal support simply isn't in the cards. While your core drivers like video, sound, and networking are likely to function, the special drivers designed for laptop hardware like easy access buttons, advanced video functionality, and add-on hardware like USB GPS dongles may not function correctly if at all. While these may sound like unnecessary add-ons, you may find that not having them reduces your appreciation for your laptop.

Hyper-V never sleeps. The installation of Hyper-V to a machine automatically disables the sleep and hibernate functionality on that machine. While most desktops rarely use these functions, laptops do all the time. Any time you close the lid on your laptop with Windows Vista, you're likely to invoke the sleep or hibernate functionality. With Hyper-V installed you may find that the laptop simply remains powered on and heated up with fans running. If you're the type to close the lid and quickly drop the laptop into your travel bag, you might find an overheated and battery-drained result down the road.

Travel-sized Hyper-V doesn't perform as well. Although reports abound on the Internet about individuals who have found substantial improvement in performance with the jump from Vista to Server 2008, the experiences of this author haven't been nearly so rosy. Upgrading from Vista to Server 2008 on a recently-purchased Centrino Duo laptop fully stocked with four gigs of RAM actually reduced overall performance. This is due to a couple of factors. First, processes completed by Hyper-V tend to increase the amount of time required for logging in. This, combined with the inability to sleep or hibernate, means that the daily workflow as one moves from site to site takes just that much longer. Second, running any virtual machines whatsoever takes away resources from the primary partition. Consequently, using Hyper-V for what it's supposed to do impacts performance for everything else.

One solution to all of these limitations is to create a dual-boot that combines the two OSes. A number of speakers and instructors who talk on Hyper-V currently use this configuration while on the road. Server 2008 provides the experience needed to demo Hyper-V's capabilities, while Vista enables all the other bells and whistles needed for life on the road.

If you're thinking about creating your own travel-sized Hyper-V, consider these issues with using Server 2008 as your primary operating system. While its "Desktop Experience" feature may make it look more like Vista, other factors are in play that can reduce your overall experience.

ABOUT THE AUTHOR:Greg Shields, MVP, is a co-founder and IT guru with Concentrated Technology (www.concentratedtechnology.com) with nearly 15 years of IT architecture and enterprise administration experience. He is an IT trainer and speaker on such IT topics as Microsoft administration, systems management and monitoring, and virtualization. His recent book Windows Server 2008: What's New/What's Changed is available from SAPIEN Press.

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