Linux and virtualization are two of the main pillars that San Jose, Calif.-based Cisco Systems Inc. is using to transform its data centers into a unified pool of on-demand IT-as-a-service resources that will make IT more efficient and cost-effective, a business enabler instead of a roadblock.
"Virtualization will drive the adoption of Linux," predicted Sidney Morgan, Cisco's senior IT manager. "Linux helps drive down the cost of maintenance… and virtualization reduces application provisioning time, capital investment and software maintenance. It has a strong ROI."
VMware Inc. agrees.
Eric Horschman, VMware's director of marketing, said the "impressive" growth rates of virtualization and Linux are "closely linked." Virtualization has greatly lowered the barriers that previously impeded Linux adoption and, conversely, contributed to Linux's accelerated growth rate in the data center, he said. VMware's Virtual Appliance Marketplace now offers more than 1,000 appliances for Linux deployment, he added.
While it's tough to quantify how much virtualization has boosted Linux adoption in the last few years, industry analysts cite a number of reasons why virtualization should boost the Linux platform in the future.
In a recent report for the
"Linux is highly compatible with two of the hottest trends in the industry: virtualization and cloud computing," wrote Al Gillen, IDC's vice president of system software. "Customers using Linux today will continue to increase their deployments of virtual instances of Linux operating systems aboard existing servers."
Other analysts have pointed out that virtualization, by initiating change in a change-adverse data center environment, opens the door for other moves, like the replacement of a proprietary OS with lower-cost Linux.
Chris Wolf, an analyst with Midvale, Utah-based Burton Group, believes virtualization has boosted Linux adoption, particularly Novell's SUSE Linux Enterprise. With no limits on the number of virtual machines per server and its "aggressive pricing," SUSE is taking market share from Red Hat Inc. and fueling a rise in Linux use for virtualization, Wolf said.
"In the enterprise, the virtualization of Linux workloads is steadily growing because the latest x86 hardware enhancements enable enterprise applications to run better in virtualized environments," he added.
One large German automaker, for example, started its virtualization effort with Windows but now is increasing the number of SUSE-based virtual machines, at least partly due to the availability of Linux-based enterprise applications, he said. Hardware improvements in this year's chipsets have boosted virtualization across all platforms by reducing memory latency, which had been a deterrent for running virtualized enterprise applications, he said. Input/output and CPU latencies were addressed in previous hardware upgrades, he said.
Cisco's Linux/virtualization adoption
Cisco began transitioning to Linux in 2002 as a cost-cutting move and began running it on virtualized servers in 2005, a year after it began a nine-year overhaul of its IT delivery system into what it calls its IT Elastic Infrastructure Services. In addition to Linux and virtualization, a third pillar of its IT-on-demand is a unified 10-gigabyte, Layer 2 Ethernet "smart" network that combines its Ethernet and IP networks into one and performs some functions now done by servers. Collectively, this on-demand IT delivery has already shaved server provisioning time from as long as eight weeks to three days currently, with a goal of 15 minutes in the next few months, Cisco's Morgan said.
More than half Cisco's servers run Cisco Enterprise Linux, a modified version of Red Hat, while 25% run Windows and the remainder are split between HP-UX and Solaris, enabling Cisco to match applications with the most appropriate OSes. Cisco began its Linux conversion with x86 applications, starting with Web servers and other light applications (many of them open source), then expanded to high-performance computing, he said.
As for virtualization, Cisco has virtualized 43% of its workload to date on VMware, with a goal of nearly doubling the volume to 80% in the next two or three years, Morgan said. And Cisco's virtualization push has definitely accelerated its migration to Linux, he said.
"We still would have migrated to Linux based on cost but our conversion was pushed to the next level because of its agility and elasticity," Morgan said. "Linux wouldn't be at 60% without virtualization. Linux has improved time-to-value and given us a quicker return on capital investment and increased operational efficiency."
Many other enterprises also are moving to Linux as the preferred OS, but others are continuing to opt for Windows, he added. Virtualization gives IT managers tremendous flexibility once they've chosen the hypervisor, he said.
Linux under the covers
Wolf added that Linux also has an increasing presence under the virtualization covers. It's part of the Xen kernel and VMware's ESX hypervisor, a major presence in the virtual appliance market and a component of some virtualization management tools, he said. Web providers are doing well with Linux and if client-based virtualization gains adoption in the next two or three years, Linux will be the OS "touching the metal" on desktops and laptops, he said.
The bottom line: "There will be a significant increase in Linux [for virtualization] in the future," Wolf said.
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