Virtualization Shootout

by [Published on 14 June 2006 / Last Updated on 14 June 2006]

This article takes an unbiased look at comparing virtualization products from Microsoft and VMware, and includes an interview with Charlie Russell, a Microsoft MVP and expert in virtualization technologies.


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The battle lines are drawn with VMware on one side and Microsoft on the other. Who will win the war of minds and hearts of enterprises concerning virtualization technologies? Back in 1999 when VMware introduced the first PC-based virtualization product (VMware Workstation) I was still working as a Microsoft Certified Trainer (MCT) at Productivity Point. It's true that VMware wasn't the first vendor to bring virtualization software to market—Connectrix actually entered the market earlier in 1997 with their Virtual PC product, but that was for the Mac platform and they didn't release their Intel version of the product until 2001. Around this time, speculation was rife in our MCT newsgroups that Microsoft might try and acquire one of these two companies in order to gain a foothold in the emerging virtualization market. Most MCTs thought Microsoft would probably go for VMware as they considered their offerings more powerful and easier to use and manage. But Microsoft surprised us and chose instead to acquire Connectrix's virtualization software assets, and soon Microsoft Virtual PC was born and then Microsoft Virtual Server. Why were MCTs so interested in virtualization anyway? Because the courses they taught were a pain to set up in classrooms, and the possibility of using virtual machines to teach Microsoft Official Curriculum (MOC) courses seemed like bliss compared to the existing method.

In any case, it was probably for the best that Microsoft acquired what may have been the lesser of the two platforms, as the result has been intense competition between VMware and Microsoft to see who can produce the best virtualization products. In other words, competition stimulates innovation, and nowhere is this more visible than in the rapidly changing virtualization arena as we can see in this interview I recently conducted with Charlie Russel, a Microsoft MVP and expert in virtualization technologies, which I'm sure you readers of WindowsNetworking.com will find interesting.

Interview with Charlie Russel, MVP

Tulloch: I'm talking today with Charlie Russel, a Microsoft MVP, popular Expert Zone columnist and author of the Microsoft Windows Server 2003 Administrator's Companion, the Microsoft Small Business Server 2003 R2 Administrator's Companion, and other popular titles from Microsoft Press. Charlie, what got you interested in virtualization in the first place?

Russel: Necessity. I write about a wide range of technologies, often loading and running multiple beta versions of operating systems and applications. I need to be able to set up test networks for many different technologies. To do that with physical machines would require a data center and a budget rather larger than I can realistically afford. With virtual machines, I have two main VM servers. Both are x64 machines with multiple disks, 4 network cards, and lots of RAM. I can set up everything from a home network to a multiple domain forest with UNIX, Linux, and Windows Server all working together.

Tulloch: Looking at the different software virtualization offerings from Microsoft (Virtual Server and Virtual PC) and VMware (VMware Server, Workstation, Player, ESX), who do you think has the edge in these technologies and why?

Russel: That’s a tough one. I use both Microsoft Virtual Server and VMWare (Workstation or Server), and I can’t get rid of either of them yet. Certainly VMWare has the undisputed edge in features, with support for USB (but only 1.1), generic SCSI devices, and drag and drop between host and guest. And its ability to run x64 guests, of course, something not supported by any current Microsoft product.

Microsoft Virtual PC isn’t an option for me, since my environment is almost exclusively x64. Microsoft VPC will not run at all on an x64 host.

Microsoft Virtual Server has some limitations, as you’re aware. But it does have some definite advantages, too. A critical one for me is that it’s a good deal more stable in an environment where you’re constantly starting, stopping and reconfiguring VMs. With VMWare, this churning of VMs will end up in fragmented memory and a serious slowdown, forcing frequent reboots.

The interface to Virtual Server is, frankly, awful. The web interface requires me to run IIS on my VM servers, something I’d rather not do, and it’s slow, awkward and annoying. On the other hand, the Virtual Machine Remote Client (VMRC) is a useful tool that lets me run VMs without having to use Remote Desktop. This is important for guests that don’t support RDP connections.

Finally, the differencing disks in Virtual Server are a real time saver for me.

Tulloch: What's System Center Virtual Machine Manager? I heard this is coming out soon for Microsoft's Virtual Server product.

Russel: Finally! Those of us who use Virtual Server have been heavily asking for an alternative to the web based management interface for a while. I’m excited about System Center Virtual Machine Manager. It has the ability to centrally manage multiple VM servers, distributing VMs across them to manage resources better. Plus the ability to have libraries of VMs that you can keep ready to go.

Tulloch: What have you heard about Viridian, Microsoft's upcoming hypervisor software?

Russel: Viridian promises to move virtualization to the next level entirely, much like VMWare’s ESX server does now, inserting the virtualization below the operating system. But with a good deal better device support. We should be able to have hot-add of network cards and RAM on a virtual machine, for example.

Tulloch: Will hardware virtualization really make a difference in terms of virtual machine performance? What's available today in this area?

Russel: Yes, it will make a significant speed difference. With direct hardware support, the software overhead is a lot less and promises to give you full speed VMs with minimal impact to the host system. The first CPUs from Intel that support hardware virtualization are shipping now, and those from AMD should start shipping very shortly. The open beta of Virtual Server 2003 R2 SP1 includes support for the Intel hardware virtualization in beta 1, and will have the AMD virtualization support in beta 2 later this year.

Tulloch: What are the main uses of virtualization you've seen in the enterprise?

Russel: Really two key scenarios, I think – server consolidation and deployment testing. Server consolidation allows enterprises to support special purpose servers, even those running older, legacy applications and operating systems, on modern, fully supported hardware. Many legacy line-of-business applications can pose a problem for IT departments. They often can’t be easily replaced or updated, but are still running on older servers that are long past the point of being economically maintained on support, but can’t be easily moved to modern hardware, and may require operating systems that are also well past their support life. By moving these applications to virtual machines, you can dump the old hardware while still providing an environment for the application that it supports.

The other scenario is deployment testing. Rapid deployment of patches for operating systems and applications has become a necessity these days. We all struggle between the twin horns of trying to adequately test a patch to ensure it doesn’t break anything critical, and not leaving our networks exposed to the latest malware that is attacking it. By having a well thought out and configured virtual test network we can easily and safely test patches as soon as they are available.

Tulloch: What about Virtual PC Express which will be available in Vista Enterprise/Ultimate editions? Will this be one of the features that may help drive adoption of Vista in enterprise environments? It seems like virtualization is more and more becoming the preferred approach to dealing with application compatibility issues as new versions of Windows are released.

Russel: Virtual PC Express will be an interesting addition to these premium SKUs, but I'm not sure they'll make all that much difference in the enterprise. Frankly, I think the pre-built, single purpose, run-only VMs that VMWare makes freely available, along with their free VM player, is a more interesting special purpose compatibility solution.

Tulloch: Anything else you'd like to add?

Russel: Yes. Just that if you’ve tried virtualization in the past, and thought it unreliable, horribly slow, or more bother than it was worth, you really should re-examine that now. Both VMWare and Virtual Server have made significant strides in the last year or so and I think you’ll be pleasantly surprised. And modern processors have really changed the dynamic, making virtualization very attractive indeed, especially given the price points for the software, and the very beneficial licensing that Microsoft introduced with Windows Server 2003 Enterprise Edition R2.

Tulloch: Thanks for giving us your time, Charlie, and sharing your expertise with WindowsNetworking.com's readers!

Further Resources

Also see my previous virtualization articles here on WindowsNetworking.com:

Find more virtualization articles and tutorials at VirtualizationAdmin.com!

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