Linux server users are reaping the benefits of virtualization more than those running Windows.
Microsoft's restrictive and confusing licenses are a big reason for holding back Windows customerson virtualization. The company's foot-dragging on VMware and Xen support, plus Hyper-V's relative lateness and immaturity, are also contributory factors
A report by Gabriel Consulting Group, an analyst firm, has found 40 per cent of "heavy" users of Linux have virtualized more than half of their x86 systems compared with just 29 per cent of Windows users.
Those running Linux in their data centers are using virtualization to consolidate servers by a rate of between five and 10 to one, while those running Windows are rapidly running out of electrical capacity and space in their data centers.
Sixty two per cent of those running virtualization with Linux reported "major benefits" compared to 48 per cent of Windows customers mixing Windows and virtualization.
Gabriel surveyed 187 data-center personnel for its annual x86 Server Vendor Preference survey, from June that has just escaped into the public. The survey found that most work in mixed environments running both Windows and Linux, although a "significant number" had decided to standardize on one operating system.
"We found that Linux-centric customers in our survey have implemented virtualization in greater numbers, to a greater extent, and are getting more benefits from virtualization technology. Windows-centric customers have also adopted virtualization, but not to the same degree, and they do not report receiving the same level of benefit," the report's author, Dan Olds, wrote here (PDF).
Simplified licensing is one of the biggest reasons Linux has done so well on virtualization - Red Hat, Novell and others charge for support on a per-server basis.
This is where the wheels fall off for Microsoft users.
Navigating Microsoft's complicated licensing is one problem. As well as buying a server license for products like Windows or SQL Server, organizations must also calculate the number of Client Access Licenses (CALs) for those who'll access the software.
And not all of Microsoft's licensing is virtualization-friendly, as the analyst firm Directions on Microsoft notes, Standard editions of products such as SQL Server, and Windows must be assigned to a specific server for at least 90 days before they can be re-assigned to another server.
This is a major obstacle if you want to use virtualization as a migration tool, such as putting Windows 2000 or 2003 servers on virtual machines for application compatibility while you upgrade your physical servers to Windows Server 2008.
In common with Directions on Microsoft, Gabriel found that customers are also purchasing volume Windows licenses to ensure they are covered for every system running on a virtual machine.
Gabriel also notes that Microsoft was, until relatively recently, unwilling to support its software running in VMware or Xen hypervisors. This left customers to support themselves or remove virtualization and then re-install it to qualify for support from Microsoft.
Hyper-V, meanwhile, lags on features, functionality, and management capabilities compared to VMware and Xen that are being used for Linux.
In its messaging Microsoft promotes the total-cost-of-saving benefits of using Windows compared to Linux. The company points to the hidden costs of Linux, in terms of support, features and integration compared to Windows.
According to Gabriel Consulting, it might have been possible to make the case a few years back that providing support for Linux was difficult, due to a lack of skills, but this isn't the case today. "The ability to implement technologies such as virtualization, for example, tends to be easier with Linux," the report concludes. ®