I definitely recommend choosing a Linux based server OS. Best will ultimately come down to your specific needs, but the way I see it, Debian, CentOS, and Ubuntu are your three main choice for a variety of different reasons.
Debian
First developed back in 1993, Debian is one of the oldest Linux distributions currently in circulation. Although it’s entirely community driven (and developed), it’s nevertheless supported by a surprisingly organized network of professionals and enthusiasts, who work together to keep things running smoothly and efficiently, with updates rolled out fairly frequently. It’s incredibly versatile, supporting a wide variety of different packages and rarely requiring a reinstall. This makes it quite well-suited for running a dedicated application server.
Compared to other distros on the market, Debian has three primary disadvantages. The first is that it is most assuredly not a distribution for non-experts. If you don’t know your way around Linux, I’d strongly advise looking for a different distro on which to run your server.
The second is related to cost – though whether or not this is to be considered a disadvantage depends entirely on the user. Since Debian is completely free, it naturally lacks an option for paid support. What that effectively means is that if you run into trouble, you’re looking to either your own team or the community.
Lastly, Debian tends to lag behind a bit in software updates compared to its competitors.
CentOS
CentOS is noteworthy for two reasons.
Firstly, it’s basically a free version of Red Hat Enterprise Linux – the most widely-supported distribution in corporate IT. By association, this means that CentOS also enjoys widespread enterprise support. That alone gives it considerable clout, and effectively makes it the only sensible choice if you’re looking for a low-cost alternative to one of the mainstream server options.
As an added bonus, working with CentOS means you’re building the skills to work with RHEL.
Secondly, it’s also one of the most stable, secure, and hardened community-driven distributions around. This security makes it a very good choice for anything Internet-facing, while its reputation for stability means that you can rest easy using it to run mission-critical servers.
CentOS isn’t perfect, of course. Historically, the distribution’s software repository was somewhat outdated and disorganized, while updates were both eclectic and unreliable. Given that CentOS now has official Red Hat support, however, these issues seem a moot point.
Ubuntu
Although Ubuntu itself is primarily a desktop Linux distribution, the brand also includes one of the most powerful free server distributions around. Ubuntu Server boasts a fast and frequent update cycle and comes bundled with a useful and diverse set of package groups. In addition to this, it’s also got an option for paid support which includes training and online services such as Landscape and Ubuntu One.
The best feature of Ubuntu – and the thing that makes it such a formidable choice – is that it features a unified package repository for all its different versions. This gives it an unprecedented level of versatility, allowing administrators to easily switch between server kernels until they find one that suits them.
