VMware Blasts Microsoft's Virtualization Licensing Policies

In a multi-page white paper posted Monday on its Web site, the Palo Alto, Calif. leading virtualization software company came out swinging, alleging that Microsoft is "forcing" its virtualization APIs and formats on the industry and leveraging its leading server applications such as Exchange, SQL Server and Windows Server to force customers to use Microsoft's virtualization offerings.

Microsoft currently offers a standalone Virtual Server 2005 and Virtual Server 2005 R2 but is busy building its next generation virtualization hypervisor into its next major Windows server upgrade, code-named Longhorn. The hypervisor, code named Viridian, will ship as an add-on to the Longhorn Server but eventually will be integrated into the server operating system, Microsoft promises.

That could stem the popularity of VMware's software layer, which resides between the bare metal server and applications, as a substitute for the operating system.

VMware says Microsoft's licensing restrictions are intended to force customers to use Microsoft's standalone offerings and in the future Microsoft's Viridian hypervisor over rival platforms.

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"Their tactics are focused on software licensing and distribution terms for SQL Server, Exchange, Windows Server, Vista and through the APIs and formats for virtualized Windows," according to the white paper, which highlights seven ways Microsoft is allegedly forcing customers to its own solution.

"Microsoft does not have key virtual infrastructure capabilities like VMware's Vmotion and [is] making those either illegal or expensive for customers; Microsoft doesn't have virtual desktop offerings, so is denying it to customers; and Microsoft is moving to control this new layer that sits on the hardware by forcing their specifications and APIs on the industry."

VMware's flagship VMware ESX server and Virtual Infrastructure platform dominate the virtualization category with a commanding lead. VMware, which generates about $1 billion a year in revenues, was acquired by EMC in 2004.

VMware seven objections are:

&#149 Microsoft offers top virtualization support for only premier-level support customers, inherently limiting the ability for many customers to get technical support for competitive virtualization platforms;

&#149 Microsoft's "restrictive terms" on the use of published virtual machines, or appliances, is unfair to users. Microsoft, VMware claims, restricts use of VHD formatted virtual machines to Microsoft Virtual Server and Virtual PC only;

&#149 Microsoft restricts customer choice by configuring its VHD virtual machines to de-activate if they are run on any virtualization offering other than Virtual PC or Virtual Server;

&#149 Microsoft's VHD licensing agreement prevents users from converting the VHD format into any virtual machine format, thus preventing compatibility with competitive platform and preventing translations into VMware's formats;

&#149 Microsoft's licensing policies discriminate against use of VMware's Vmotion and other virtualization management platforms that enable users to move virtual machines from one platform to another. VMware cites one policy that requires "permanent assignment" of operating system licenses to specific systems and simultaneously restricts the movement of those operating system licenses. VMware claims that one policy, for example, is designed to restrict movement of Windows server licenses more than once every quarter.

&#149 Microsoft imposes significant restrictions on desktop virtualization including the movement of desktop virtual machines, restrictions on OEM versions of Windows, and restrictions on virtualization on Windows Vista. VMware charges that this makes it difficult if not impossible for end users to choose competitive platforms. VMware attempts to back its case by pointing out that VMware once had an OEM license to redistribute Windows in a VMware VM but has not been able to renew that since 2003.

&#149 Finally, VMware claims that Microsoft's virtualization APIs for Longhorn are proprietary. The APIs handle communication between Windows and the Microsoft hypervisor. VMware said Microsoft opened up three virtualization APIs last June but they cannot be used by virtualization vendors.

Microsoft released a general response to VMware's charges on Monday, claiming that it is being open by publishing APIs.

"Microsoft believes the best approach for customers lies in establishing a foundation of cooperation between vendors, which is why we strive to regard virtual machines and virtualization technology the same way. Windows server licensing offers a level playing field to all," according to a statement attributed to Mike Neil, senior director of Microsoft's virtualization strategy. "To encourage interoperability, we openly share technology and have published a set of APIs for all our commercially available virtualization products today and provided documentation on APIs for the hypervisor that will be part of the next version of Windows Server, codenamed Longhorn. "