In many ways, there's never been a better time than now to make a big enterprise move to Linux. Code is mature, competition is fierce, and there are only a few serious contenders. However, each one of these Linux distributions has a distinct feature set, migration path and face for accountability. Picking the right one for your enterprise is crucial.\n\nBut the decision can be made easier if you take a few straightforward considerations into play. When you're picking a Linux distribution for the enterprise, you want to be familiar with the options\u2014so you know which ones have the features and support you need\u2014and you also have to take a cold look at your existing infrastructure, the kind of support staff you have, and what kind of accountability with which you're most comfortable.\n\n\nKnow Your Options\n"We conduct a comprehensive due diligence assessment for any enterprise-class application, system or service," says Greg Ashley, senior associate CIO at the University of Georgia. As part of this process, Ashley says that the organization evaluates all available options. And that's the first step a CIO should make in choosing the right Linux.\n\nThe first two distributions to look at are the ones that have the "Enterprise Linux" gravitas in the industry today. That's Red Hat Enterprise Linux and Novell SUSE Linux Enterprise, says Jay Lyman, open-source analyst for the 451 Group in New York.\n\nLast month, Red Hat Software released Red Hat Enterprise Linux 5, the latest in its enterprise-caliber Linux, and which now includes Xen virtualization.\nIn contrast, Novell's SUSE Linux Enterprise 10, which came to market with Xen virtualization last summer, is billed as "the only enterprise-grade Linux platform offering a complete solution for your mission-critical needs."\n\nWhile both are today's Linux enterprise stars, other distributions are rising. Ubuntu, for instance, has been a\ndesktop success story. And now, it's taking on the enterprise. The French parliament will install Ubuntu on more than 1,000 desktops this summer. Ubuntu also has partnered with Sun to win support and placement on some of the latter's new Niagara servers, while building on the distribution's stellar desktop reputation.\n\n"Frankly, we haven't really seen anything like that in Linux\u2014and it's been the solid leader for at least two years running now, so it's not a fad," says Lyman. "I think normally when you talk to analysts and industry observers, they'll say it's going to be hard to impossible for anybody to gain on Red Hat and Novell, but a partnership with Sun Microsystems and the attraction that Ubuntu has had shouldn't be underestimated."\n\nAnd there are others. Oracle's Unbreakable Linux is essentially Red Hat, but with Oracle providing the upgrades and support. Some companies have built distributions on their own Linux desktop technologies and are now vying for the enterprise. Mandriva released Corporate Desktop 4.0 last month and has a number of active partnerships, while Xandros provides a Windows-like environment, which is a big selling point: "Your Windows admins won't be completely thrown off by Xandros," says Lyman, who also sees an opportunity for some of these other distributions in just the right niches. According to Lyman, Debian, for example, has a place in enterprise data centers. (The city of Munich started its 14,000 PC migration to Debian last year.)\nLine Up Support\nOnce you know what's out there, the first question to ask is where the accountability will rest. What can your team handle, and what kind of support and services program will it need? Because when you commit to a distribution, support is as important a consideration as is the software.\n\n"It's more than just buying the license\u2014it's the support-partner relationship," says Amy Niersbach, platform architect for the city of Chicago. "It really makes a success of that type of implementation."\n\nAlthough Niersbach says that Novell as "excellent support," the city made its decision to go with Red Hat on its 80 servers for other reasons.\n\n"A lot of people are skeptical to buy Red Hat because they're worried about support\u2014I still hear that from time to time," Niersbach\nadmits. But she says CIOs should also consider third-party support\nas a viable option. "Dell offers support, HP offers support, and that's an attractive offer for companies."\n\nSince Niersbach's enterprise buys a lot of HP servers, it decided to\nenter a partnership with HP, which she says has "a lot more to bring to\nthe table" owing to its long history in the UNIX business.\n\nFor some, picking out a partner or third-party advocate also provides\nthe accountability answer they need\u2014and even brings down total cost\nof ownership. According to Ashley, this has proven to be the case at\nthe University of Georgia.\n\n"We typically engage a partner that provides guaranteed support for\nany enterprise-class system or application," he confirms. "Our\nexperience and research has demonstrated that this is instrumental in\nmaximizing system or application availability at the lowest total cost\nof ownership."\n\n\n\nLook at Your Infrastructure\nLyman says that your existing infrastructure is also going to be a\nmajor factor in the decision. It doesn't make sense to adopt a\ndistribution that isn't suited to what your enterprise already has in\nplace.\n\nLook at your enterprise architectures, and make sure they're\nwell-supported with whatever distribution you're considering. Most\ndistributions publish lists that detail their supported hardware; Red Hat does, and Novell has separate lists for the server and the desktop.\n\nThe distribution you choose should also play well with the vendors on which you\nalready rely. It was vendor interoperability that swayed the decision for Niersbach. "We're a big Oracle shop, and Oracle's certified on Red Hat," she says.\n\nRed Hat's Oracle and vendor interoperability has helped it win over\nmany an enterprise. This was the case for Wotif.com, the popular Australian-based online business and leisure accommodation booking service. Its servers handle nearly 2.5 million user sessions a month.\n\n"From a commercial perspective, Red Hat has strong relationships with\nleading vendors, such as Oracle and hardware vendors," says Paul Young, Wotif.com's CIO. "Continuing our association with Red Hat is in line with our ongoing strategy of alignment with key vendors that produce high-quality open-source software that adheres to open standards."\n\nOn the other hand, if you're running only a few applications on Oracle or you don't have Oracle at all, you might lean toward Novell's SUSE Linux Enterprise\u2014especially if you have Windows interoperability needs, which Lyman believes is an important differentiator for their brand of Linux.\n\n"That opens it up to a Windows shop, and obviously they might lean toward SUSE Linux," he says.\n\nLast fall, Novell announced the beginning of a collaboration with\nMicrosoft; Novell's senior manager for public relations, Kevan Barney, says this collaboration is now beginning to bear fruit, pointing to recent advances in virtualization, Web services for managing physical and virtual servers, directory and identity interoperability, and document format compatibility.\n\nOther enterprises might even let the vendors do the decision-making\nfor them. That's the experience of Neil Truby, director of Ardenta Limited, a U.K.-based consultancy that helps\nenterprises deploy Linux. He says that customers often don't know the differences between distros, and will eagerly defer to their trusted resellers and application vendors for a lead.\n\n"For example, customers wishing to run an IBM Informix database will pay, as part of their license, a substantial proportion of that license for\nvendor maintenance," says Truby. "In this case, the vendor will support the database only on SUSE or Red Hat, so even if we might think that an alternative\u2014say, Ubuntu\u2014might have its merits, our advice to the customer is that it would be madness to invalidate the maintenance conditions from IBM."\n\nAsk Your People\nFamiliarity was another key reason the city of Chicago decided to deploy Red Hat.\n\n"Our system engineers were familiar with it, so we had the knowledge base in-house," says Niersbach.\n\nLyman suggests that CIOs facing a Linux decision should look for an internal champion, someone who knows the field and has a favorite. If you have one or more of these people, they will be critical keys in whatever Linux you deploy.\n\n"If you've got a champion in-house, that goes a long way," says Lyman. "You might have a couple folks on your IT staff that are totally into Debian Linux, and that might sway you to consider that."\n\nThat's exactly what happened at Hewlett-Packard, where the decision was made to employ Debian "because of the long history of technical collaboration between HP's internal engineering community and the Debian project," says Bdale Garbee, chief technologist of the HP Open Source & Linux Organization. "HP employs a number of current Debian developers, and has used Debian technology in various products over the years."\n\nAccording to Lyman, interacting directly with the communities behind\nsome of these Linux distributions and open-source projects is going to\nbe an increasing trend.\n\n"It's the same way that open source has crept into enterprise infrastructure: It's the developer team using it," he says. "Maybe the CIO isn't aware of it, or it isn't a huge priority for him or her, but nevertheless it's in use. We think that will continue to grow, and it will become even more acceptable as these communities mature and as companies watch each other to see how they do things."