If there was any remaining doubt about the software virtualization market going mainstream, allow it to be quelled now. In the wake of Microsoft's ever-aggressive pricing changes to the its Virtual Server product line, virtualization giant VMware announced that it was rebranding its VMware GSX Server product as VMware Server and offering it to customers for free. Consider the gauntlet thrown down.

The potential market for this software is humongous. With more companies looking to consolidate aging Windows NT-based servers, virtualization has emerged as a major market opportunity. And of course, the traditional virtualization markets--testing, Help desk, and so on--remain important as well.

VMware's free offering follows a spate of announcements from Microsoft that resulted in incredibly low prices for Virtual Server. The original Virtual Server 2005 version, for example, cost $999 for the Enterprise Edition and $499 for the Standard Edition. With Virtual Server 2005 R2, however, Microsoft has slashed prices, Crazy Eddie style. The Enterprise Edition now costs just $199 and Standard Edition is just $99. And for a limited time, customers that purchase Windows Server 2003 R2 Enterprise Edition can get Virtual Server 2005 R2 Enterprise Edition for just $99. That offer is good through the end of June 2006.

Such prices are unheard of in the server market. Indeed, Microsoft's client-side virtualization offering, Virtual PC 2004, is actually more expensive. The full retail price of that package is $129, and Virtual PC is much more limited than Microsoft's server offerings.

This, then, is the market VMware found itself competing in. And its solution, VMware Server, is somewhat inspired. Like the company's earlier GSX Server offering, VMware Server uses the same high-performance virtual machine (VM) format as VMware ESX Server and VMware Workstation products. The VMware solutions also offer several features that aren't available in Microsoft's products (e.g., Linux host system compatibility--Virtual Server runs only on Windows Server, of course) and USB support from within guest environments. Also, because VMware has been supporting Linux guest environments all along, its Linux support is superior (Microsoft only recently reinstated Linux guest support in Virtual Server 2005 R2).

In my opinion, one of the biggest improvements to VMware Server is that it finally supports 64-bit x64 guest OS installations, whereas Virtual Server doesn't. I think it's obvious by now that native x64 environments, such as Windows 2003 x64 Edition and Windows XP Professional x64 Edition, are off to a slow start, and VM support should help developers start testing their solutions on x64 systems.

As a free entry-level product, VMware Server won't meet everyone's needs, but it's certainly a compelling product for the developers, branch offices, and small businesses that VMware is targeting. Compared to its ESX Server-based brethren, VMware Server is limited in a few ways and is ideal for testing and legacy (i.e., NT 4.0-based) server consolidation scenarios. For example, VMware Server can't cluster VMs across different hosts or provide native SAN access to guest machines. It does support 2 to 16 CPUs per server and as much as 64GB of RAM in the host system (like ESX Server), but it can typically host only two to four simultaneous VMs per processor core--about half the capacity of ESX Server.

The battle for the virtualization market is like any other competition in the PC market: Both Microsoft and VMware would like to see their VM formats become the de facto standard, and each companies' moves should be seen in that light. Microsoft has established itself as the low-end, safer vendor, if you will, and it's clearly targeting specific markets with its Virtual Server products. Meanwhile, VMware appears to have the better performing and more versatile solutions, and you can't argue with the pricing of either solution.

One other differentiator is that VMware and its partners are starting to offer prebuilt virtual environments for sale and for free download, which offer ready-made, plug-and-play OS and application installs. This could be an interesting application-deployment scenario for the future, and I recall Microsoft admitting to me previously that it was examining the possibility of using its VHD VM format as a standardized software-deployment format going forward. This is a big step up from the first few virtualization solutions, which were designed basically as a way to run Windows applications on top of Linux.

In any event, VMware Server is free, and you can download a beta version of the product from VMware's Web site. I recommend you give it a shot. At this price--or more appropriately, lack of price--VMware Server is certainly worth examining.

http://www.vmware.com/products/server/