Linux on Big Iron

Open-source operating system making itself at home even on large servers.

Linux on mainframe systems? Dont laugh. Dave Ennen isnt. The technical support manager at Winnebago Industries Inc. recently oversaw the deployment of Version 7 of SuSE Linux AGs Linux operating system on an IBM zSeries mainframe to run his companys e-mail server supporting 700 users. Ennen, in Forest City, Iowa, said the move allowed him to avoid spending $150,000 on new hardware and software for a Microsoft Corp. Exchange upgrade. The Linux e-mail system cost Winnebago $26,000.

"Not only did we find a more cost-effective e-mail option, but it also showed us that Linux is ideal for enterprise applications and for our mainframe environment," said Ennen. "Im not planning on buying any more Intel [Corp.]-based servers. As long as we can integrate new applications to our legacy side using Linux, Im going to focus on that."

Having established itself over the last few years as an enterprise file and print server and as a Web server, Linux is now stepping into the ring with the big boys, running on the big boxes—even mainframes, in some cases—and being used for business-critical applications such as database software. In other words, Linux has come a long way from being Linus Torvalds student computer project.

The need to cut software licensing costs and to consolidate applications on fewer servers are two factors driving Linuxs appearance on larger multiprocessor systems and even mainframes, experts say. Pushing the trend along is the maturity of the 15-month-old Linux 2.4 kernel and the slow-but-steady appearance of more packaged enterprise applications running on Linux. There still arent enough commercial enterprise applications available on Linux to encourage a wholesale shift of enterprises to big-box Linux yet, however. And robust Linux kernel support for very large servers—those with more than eight processors—will be needed for the open-source operating system to become a true competitor to Unix, Windows and OS/390 on larger servers.

Still, say experts, Linux running enterprise applications on large servers is gaining momentum.

"People are really starting to use Linux heavily right now," said Chad Robinson, an analyst at Robert Francis Group Inc., a consultancy in Westport, Conn. "Enterprises are relying on it for everything from trading desk applications in brokerage houses to Web server farms, application servers farms, even database servers. We are now seeing companies run their mission-critical applications on Linux."

While Linux has yet to make headway on corporate desktops, there are now strong indications of the operating systems mainstream acceptance in corporate server rooms. Linux garnered a 20 percent share of corporate database deployments—including DB2, Oracle Corp.s Oracle and other enterprise products—in 2000, according to research company International Data Corp., in Framingham, Mass. Thats up from 10 percent in 1999. Ten percent of users said they were running at least one mission-critical application on Linux, such as ERP (enterprise resource planning), customer relationship management or human resources application, up from 4 percent in 1999.

Whats more, IBM officials said 11 percent of the mainframe mips (million instructions per second) shipped by the company in the fourth quarter of last year were configured to run Linux.

Software vendors are responding to this increased interest by enterprises in running Linux on larger servers. SuSE Linux, of Nuremburg, Germany, announced this month that its 64-bit SuSE Linux Enterprise Server 7 operating system for IBMs eServer zSeries mainframe would be available in May. And, at LinuxWorld in New York earlier this year, Computer Associates International Inc., of Islandia, N.Y., announced 23 products running on Linux, including enterprise storage management and security software. IBMs Tivoli unit is now porting its products to run on and manage multiple Linux images on IBM zSeries mainframes.

ERP and other enterprise application vendors are following suit. SAP AG, of Walldorf, Germany, last year ported its MySAP software to Linux, allowing enterprise users to handle tasks such as accounting, ordering and joint inventory with business partners using the open-source operating system. The number of enterprise applications on Linux from which to choose is still relatively sparse, however. SAP, for example, still hasnt migrated its core application suite to Linux, nor have most other leading ERP vendors. More will begin to do so soon, however, experts predict.

"Were in the middle of the adoption curve right now, so were seeing a number of companies working on porting their software to Linux," Robinson said. "Linux has proven itself appropriate and applicable to enterprise-class customers. And for the applications that you dont see yet, I would say that in the next year or two, youll see those ported to Linux just as they would be for any other operating system."

How fast should managers move business-critical applications onto large servers running Linux? First, experts say, theres no point in a company that does not already use mainframes rushing out to purchase one for the sole purpose of running Linux. Linux on mainframes makes sense only for enterprises that already run big iron and want to reap cost savings associated with server consolidation.

But, say experts, other companies—particularly those already planning to upgrade to new versions of enterprise-class software—may want to consider running them on larger, multiprocessor Linux servers.

Thats what online financial services company E-Trade Group Inc. plans to do. The Palo Alto, Calif., company, which requires enormous stability, scalability and uptime, announced at LinuxWorld this year that it was dumping its servers from Sun Microsystems Inc. running Solaris in favor of servers from several vendors that run Linux.

Its clear the migration will affect some large, mission-critical applications. Eventually, the company plans to replace more than 300 customer-facing databases, application servers and Web servers with various boxes running Linux, said Joshua Levine, chief technology officer at E-Trade. E-Trade executives hope to see savings associated with licensing fees and management costs.

For companies with mainframes and no immediate need to replace them, Linux on big iron may make all the sense in the world, experts say. "When you have such a big piece of iron, youre supporting an entire infrastructure, and it makes good sense to consolidate all the pieces of that infrastructure into one single piece of hardware," said Francis Groups Robinson. "Both Linux and mainframes are known for stability and scalability, so theres no better uptime guarantee."

The need to ensure uptime was one reason Winnebago chose to run Linux on its mainframe. Last year, faced with an expensive upgrade to Exchange 2000, IT managers at the motor home and recreation vehicle manufacturer decided against the move and instead proposed running their e-mail system on Linux on the companys mainframe.

The company had success using Linux for domain name servers, Web serving and file sharing on its IBM S/390 mainframe running the Virtual Machine/Enterprise System Architecture operating system. After Winnebago officials decided they wanted their e-mail system on a reliable system, they chose to upgrade the companys mainframe, adding a second processor using IBMs virtualization technology, zVM, to run several Linux servers on a single mainframe.

The company deployed Bynari Inc.s Insight Server Enterprise Edition 3.0 for e-mail on Version 7.0 of the Linux operating system from SuSE Linux. The e-mail system went live in December. Altogether, the company has 128 mainframe mips. Its using between 7 percent and 10 percent of those to run Linux and the e-mail system.

Despite Winnebagos success with e-mail on Linux, Ennen said he has no plans to move legacy business and mission- critical applications such as order management or accounting onto his Linux mainframe just yet. While he is thinking about consolidating the work of 40 additional servers currently handling file serving and other applications onto the Linux mainframe to gain additional efficiencies, he said there is no point to moving off legacy databases and order management modules already running on OS/390.

"Were focusing on being able to use the systems we already have on the legacy side, so moving just to move does not make sense," Ennen said. "The question is whether or not an application is critical enough to run on our mainframe. And if it is critical enough, its probably already working on the mainframe."

Experts agree that there are still a number of enterprise applications for which Linux is not ready. One reason is simply that many commercial enterprise applications have yet to be ported to Linux. Another has to do with scalability. It wasnt until last January, when the 2.4 kernel was released, that Linux—at least in theory—could support up to 32 processors, up from 16 processors in the 2.2 version. Yet operating systems such as Red Hat Linux from Red Hat Inc. support only up to eight processors.

It wont be long, however, before Linux is every bit as scalable as any other operating system. The next kernel release, Version 2.5, may improve on Linuxs multiprocessing support. Meanwhile, researchers in the scientific community are working to allow Linux to run on very large clusters of processors.

One such endeavor is taking place at the San Diego Supercomputer Center, where researchers are using 40 clustered Compaq Computer Corp. ProLiant DL 360-series servers and four clustered ProLiant DL 380-series servers running Red Hat Linux 7.2 to contribute clustering research to the National Science Foundations TeraGrid project.

The $53 million projects purpose is to build the next step in supercomputing: a Linux cluster that is capable of 13.5 trillion floating-point operations per second and is spread out over four locations, including the SDSC, said Philip Papadopoulos, associate director and group leader of distributed computing at SDSC.

No enterprise is likely to need that kind of computing power any time soon. Still, its solid proof that, with scientists and open-source developers around the world continuing to build out Linuxs potential, its only a matter of time before the open-source operating system is a match for any operating system on any platform. Even mainframes.