In a typical corporate data center, you can't use just any version of Linux. Corporate Linux needs to be reliable, and there are several requirements for getting this reliability. While most IT shops know the Linux OS has earned its place in the data center, what is the best Linux distribution for your enterprise?
First, be sure the Linux distribution communicates well with your server hardware. Next, check that your application vendors support your Linux distribution. You also need a guarantee that your Linux will be maintained for the next couple of years; no one in the data center is happy to upgrade a working platform every 18 months.
Finally, you need to be able to escalate when trouble arises. Considering all these requirements, only a few Linux distributions are serious candidates for your data center: Red Hat Enterprise Linux (RHEL), SuSE Linux Enterprise Server (SLES), Oracle Unbreakable Linux (OUL) and Ubuntu Long Term Support (LTS).
It's not that other Linux distributions aren't good enough; they just haven't been developed with the data center in mind. Debian, for example, is a very stable and mature Linux distribution and suitable for your most precious applications. But what are you going to do if you've installed an instance of SAP on Debian just to find out that SAP doesn't support the underlying Debian platform? Not much.
Debian -- as is the case for other distributions -- is a perfect choice for scientific environments where skilled engineers and programmers are available to offer support and maintenance. But it's not built for a data center where you need to be able to offer support on the entire stack.
So between SuSE, Red Hat, Oracle and Ubuntu, which is the best choice?
Let's talk about Ubuntu LTS first. You may have thought of installing SAP on Ubuntu LTS, but it isn't on the list of supported Linux distributions. Also, Canonical -- the company behind Ubuntu LTS -- hasn't been able to get widespread support from hardware vendors.
This leaves RHEL, SLES and OUL, which are on the list of supported distributions of most application vendors.
Most packages in OUL are just re-engineered Red Hat Enterprise Linux packages, even if Oracle has developers actively working on their Linux distribution to optimize the software to run Oracle products. For Oracle shops, OUL is a good Linux candidate. You can run Oracle databases on Oracle Linux in an Oracle Enterprise Virtualization platform, on top of Oracle hardware (formerly known as Sun). Some customers prefer to get support from the application all the way down to the bottom of the stack, while others would rather consider it vendor lock-in reinvented. But Oracle Linux still has all the features a corporate customer would need for the data center.
Deciding between Red Hat and SuSE
The most important players in the data center currently are Red Hat and SuSE. There are no official figures, but the general consensus is that Red Hat has more installations.
From my personal experience as a Linux trainer and consultant with some of the largest companies in Europe, I would guess that the Red Hat to SuSE ratio is about 4:1. Does that mean you need to buy Red Hat if you want to play it safe? There are many good reasons to do so. It is the biggest Linux vendor, it drives many open source projects, it offers innovation to the market and it has the middleware platform JBoss. If you're running Java applications on JBoss, it makes sense to do that on Red Hat (another example of support almost all the way down to the stack; Red Hat doesn't make hardware).
Still, SuSE is growing and there are several reasons for companies to choose SuSE over Red Hat. A common reason is the company is still small, which means it is easy to get in touch with the right people when you have a problem.
Some enterprises are buying SuSE instead of Red Hat because of the price. On average, SuSE is less expensive, while having features that can easily match up with the functionality Red Hat offers. And, in general, SuSE is easier to manage. SuSE offers YaST, an integrated management tool that makes tasks that are difficult to accomplish on Red Hat a lot easier on SuSE.