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.
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.
Roy Schestowitz, an ardent supporter of Linux and ardent opponent of Microsoft who runs the Boycott Novell Web site, argues that Linux gets shortchanged in surveys on market share because only "sold" OSes are counted -- and often just those sold as part of server hardware by major companies such as Dell Computer, Hewlett-Packard, and IBM.
Is it really a race?
With both OSes growing, should IT be thinking of Linux and Windows Server as either/or propositions? No.
Linux provider Red Hat sees heterogeneity ruling the day, with users deploying both Linux and Windows Server. Linux already has a large base in Web deployments but is expected to move into high-end database and enterprise application deployments, says Nick Carr, Red Hat's marketing director. Windows, meanwhile, has a large base as a server for Exchange Server, SQL Server, and file and print deployments, he notes.
"Nobody has a sort of homogeneous world anymore," Carr notes. "People tend to think that one grows at the expense of the other but that's not what's happening at the moment." That's why Red Hat and Microsoft recently agreed to let Red Hat Linux users run Windows servers in virtual machines and let Windows Server users run Red Hat Linux in VMs. "Increasingly, such servers that run in mixed environments rely on virtualization," notes Linux proponent Schestowitz.
CRIS Camera Services is an example of the mixed Linux-Windows Server environment that will keep both OSes in demand. At CRIS, Linux gets the nod for running PHP, MySQL, and Apache software, says Josh Treadwell, the company's IT director. But it relies on Windows Server for its Microsoft Dynamics and SharePoint applications. And its use of Windows Server benefits from the wide availability of Windows training certifications. "We have found college education circles around Microsoft languages," he says, noting there is no central certification for Linux.
The cost question
Possible reasons for moving to Linux include antipathy toward Microsoft and the perception that Linux is cheaper in terms of license fees, says Gartner's Weiss. Linux has an inside track with startups as well as with larger ventures such as Google, he notes -- two environments where cost or "anyone but Microsoft" concerns are key.
But the Linux financial advantage may not be real, Weiss says. When adding up the numbers for Linux deployments in a larger scalable environment, he does not see much difference among Linux, Unix, and Windows once you factor in the costs to achieve high availability, implement a global file system, and get technical support. Also, equipment expenses are a wash between Linux and Windows, he says: "Windows and Linux can run on the same hardware."
The Linux Foundation's Zemlin argues that Linux is in fact cheaper to use than Windows. One reason is the lack of licensing costs for Linux. Another is that Linux runs across a much wider variety of systems than the predominantly Intel x86-based Windows platform, he says, so you get an economy of scale across a mix of hardware. In addition to x86 serves and blades, both of which run Windows, Zemlin notes that Linux runs on mainframes, IBM Power systems, and other Unix-oriented hardware. "Linux can be a very cost-effective common denominator among these systems, he contends.
Some organizations may see cost savings from running free, unsupported Linux distros, but Gartner's Weiss says that is foolishly dangerous. A major outage or security breach without immediate access to a Linux support provider can easily wipe out any money saved from relying only on yourself. (Windows Server support is also needed, and it too requires paying a support provider.)