During the past few fiscal quarters, Margaret Lewis has seen an interesting trend in the server space: Windows is garnering a greater share of the market, while growth in Linux systems appears to be slowing.
Lewis, director of commercial solutions at chip maker Advanced Micro Devices, said that in 2000, Windows constituted about half the server operating system market, followed by Unix and NetWare at about 17 percent each and Linux at about 10 percent. Today, Windows owns about 70 percent and Linux about 20 percent, with Unix below 10 percent and NetWare barely registering.
"Looking at these large operating- system market swings, you could draw the conclusion that Linux has gotten the 'low-hanging fruit' in terms of migration," Lewis said. "Without the larger pool of Unix and NetWare users, who are ripe for migration, there is not quite the level of fuel. You could assume that Linux is now ready to settle down to a more regular growth curve representative of a more mature technology."
Lewis' observations mirror numbers in IDC's Quarterly Server Tracker, which indicate that Linux growth in the U.S. x86 server market has, over the past six quarters, started to falter and reverse its positive course relative to Windows Server and the market as a whole.
The annual rate of Linux growth in the x86 server space fell to negative 4 percent in calendar year 2006, while Windows Server growth outpaced the total growth rate in that market by more than 4 percent in 2006, IDC's figures indicate.
One of the biggest reasons for this is that migrations from Unix to Linux have slowed down markedly.
"We have seen the rate of migration from Unix slow over the past few quarters," IDC analyst Matt Eastwood told eWEEK. "In my view, this is because much of the low-hanging fruit has been moved, and the applications that remain on Unix are stickier because they are seen as business-critical and more political candidates for migration overall."
While the numbers may have cheered Microsoft executives, they drew sharp criticism from Linux supporters, who said Linux is routinely undercounted in such surveys.
Amanda McPherson, marketing director for The Linux Foundation, in San Francisco, said it is impossible to count all the Linux servers in the market today.
"Some people buy bare servers and install Linux on them, while others are recycling old Unix or Windows servers and installing Linux on them. In addition, there has been huge Linux growth on architectures other than x86, including mainframes, IBM [System p] and others," McPherson told eWEEK.
The figures also failed to consider virtualization's impact on server shipments, as customers are using virtualization to optimize boxes they had already bought.
"Since Linux is considered the better platform for virtualization, this impacts its numbers even more," McPherson said. "I don't think customers are complaining that they are getting more out of the investments they have already made."
As to whether the slowdown in Linux x86 growth was due to the fact that the most likely Unix-to-Linux migrations have already occurred, McPherson said The Linux Foundation could find no empirical data to justify the argument.
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But Novell spokesperson Bruce Lowry, in San Francisco, acknowledged it might be true that Unix migrations are easing off and that the easiest migrations have already happened. However, there is still much opportunity for Unix migrations, and there will be for a while, Lowry said.
"There are various other things that are also happening in the market, such as the use of Linux on older machines, virtualization and Linux in appliances," Lowry said. "So, the software side doesn't necessarily track with the hardware side for Linux.
"Our understanding is that even IDC continues to see growth in the Linux software business—both in terms of paid and unpaid Linux—and Novell's Linux business is growing, regardless of the broader trend."
Bill Hilf, general manager of Windows Server marketing and platform strategy at Microsoft, of Redmond, Wash., said that increased customer adoption of Windows Server 2003 in a broad range of enterprise scenarios is driving significant growth of that business.
"I spend a lot of time talking with both Linux and Windows customers and partners, and the feedback that I hear is that, in volume, Linux is primarily deployed in two workloads—high-performance computing and as Web servers," Hilf told eWEEK. "It appears that Linux server growth is moderating considerably, and, while it's certainly still a player, it's not being considered across the broad range of workloads that Windows Server is, from ERP [enterprise resource planning] to CRM [customer relationship management] to messaging and collaboration to core infrastructure, like file and print."
The fact that Windows has maintained steady growth could be the result of companies expanding their Windows-based IT infrastructures to meet the demands of users who always want to be online, said AMD's Lewis in Austin, Texas.
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"Windows-based Web hosting sites are experiencing strong growth, the Exchange infrastructure is expanding to offer unified messaging and many small businesses are moving to a real server infrastructure for basic infrastructure instead of a network of desktops," Lewis said.
IDC analyst Al Gillen pointed out that the number of servers shipped does not perfectly equal the number of operating systems in the market. This is particularly the case with Linux, where a substantial portion of the overall market opportunity comes from deployments aboard recycled servers, PCs and workstations deployed as servers, as well as Linux deployed as a guest operating system.
"This does not contradict any trending taking place on server hardware," Gillen said. "But we do need to remember that the Linux software ecosystem does not track exactly the same as does x86 hardware shipments."
Like other Linux proponents, Con Zymaris, CEO of open-source company Cybersource, in Melbourne, Australia, said that it is impossible to estimate the number of Linux systems in existence and that any such projections will likely be inaccurate.
"They do not, they cannot, capture the great majority of Linux servers deployed in production," Zymaris said. "Our company is but one data point here: Our staff has been involved in over 1,000 Linux deployments in the past 15 years, of which only a dozen would appear on the radar of research companies like IDC."
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