The Windows-versus-Linux server face-off

Linux certainly has established itself as a prominent server OS these days, pushing Unix into the background. But the open source OS shares the stage with commercial software giant Microsoft, which remains a dominant player with Windows Server.

Gartner research published this month found the server OS market shaping up as a battle between Windows Server and Linux. Gartner in other research also has found both OSes on a growth track in terms of revenue. "There still seems to be plenty of robust interest in deploying on Windows, but Linux is still very key," says Gartner analyst George Weiss.

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A lot of Linux usage is in Web server applications, but it's become increasingly common in mission-critical applications, Weiss notes. But "I don't have an indicator that says Linux is chewing up the market for Windows," he adds.

Other forms of Unix continue to fade away in what is becoming a two-OS choice for IT. "The key here is that really Linux and Windows are moving away from the pack here and it's becoming a two-horse race," says Jim Zemlin, executive director of the Linux Foundation.

Both Linux and Windows Server see datacenter growth
Regarding migration of current workloads, 43 percent of respondents in a Gartner survey at a Linux-oriented conference anticipated migrating mostly from Unix to Linux, 13 percent said they would migrate mostly from Windows to Linux, and only 4 percent said they would switch off Linux to go to Windows. Twenty-one percent had no plans to migrate workloads.

Gartner expects IT organizations to shift their focus to more-complex Linux deployments and continue a trend of migration from Unix. Gartner found that 52 percent of respondents anticipate that the total workload of their Linux server environment will increase moderately in 2008; another 25 percent said there would be a substantial increase. Only 5 percent anticipated moderate decrease, while 4 percent expected a substantial decrease in Linux workloads for this year. Respondents were three times more likely to migrate workloads from Unix to Linux than from Windows to Linux.

Although Linux growth is strong, so is that of Windows Server, according to Gartner's research. Linux was ranked by 39 percent of respondents as the OS expected to have the most growth in their datacenters during the next five years. Windows was a close second, ranked as the OS with the most growth potential by 35 percent of respondents at the Linux-oriented conference.

Based on Gartner's annual estimates for worldwide server shipment revenues, both Windows Server and Linux will increase. Windows Server sales will move from about $20 billion last year to roughly $22 billion in 2012; Linux will grow from about $9 billion last year to $12 billion in three years. But because Linux is often provided at no cost (with vendors making revenues from support contracts and other services), those numbers may not be comparable.