I have written several articles in the past concerning Enterprise Linux distributions and how they are different than other linux distributions. There are 2 such articles currently linked from HughesJR.com:

Introduction to Enterprise Linux

CentOS Review

This article is going to be a little different. It is going to recommend a free enterprise linux distro, CentOS, as the one you should pick for your Enterprise needs.

Before I start, I want to disclose that I am the lead CentOS-4 Developer and I manage the i386 and x86_64 architectures for CentOS-4, so my opinion might be a bit biased. However, I want to point out all the reasons that CentOS should be the free enterprise Linux distribution you want. {Which is the reason WHY I am a CentOS developer :)}

There are 3 main players in the paid Enterprise Linux market, Red Hat, SUSE/Novell, and Mandriva. SUSE/Novell and Mandriva do not make their SRPMS nearly as available as Red Hat, so there are no rebuild projects for SUSE/Novell or Mandriva enterprise versions. Since I am focusing on free (as in $$$$) distributions, SUSE/Novell and Mandrava are not considered for this article.

Ubuntu has extended the lifetime (support cycle) for Ubuntu 6.06 LTS (Long Term Support). This product is fine for base linux products (LAMP server, MySQL server, Samba server, etc.). There are not nearly as many major 3rd party applications (like Oracle, several Exchange replacement mail servers, etc.) which work as is on Ubuntu LTS as there are for the 3 paid Enterprise Linux vendors. When those products are available for Ubuntu LTS, it will be a major enterprise player, but for now I would recommend a RHEL rebuild project instead.

First, who are the current Enterprise Linux rebuild players (including non-free):

CentOS (free)
Scientific Linux (free)
White Box Enterprise Linux (free)
Tao Linux (retired - now part of CentOS)
Lineox Enterprise Linux (Non-Free, subscription required)

(the above 5 are the top RHEL rebuilds as listed on the DistroWatch Major Distributions page. I agree that those are the major players in the RHEL rebuild arena.)

Here are some other distributions that are RHEL rebuilds:
Pie Box Linux (non-free, requires subscription)
xOS Linux(free)
StartCom Linux(free)


Which of those is the best free distribution? I would say it is CentOS for the following reasons:

1. CentOS was rated 8th in Web servers on the Internet in November 2005 by this Netcraft survey. The number of Internet Providers using CentOS is steadily increasing.

2. This presentation produced by IBM Brazil concerning CentOS.

3. The fact that several OTHER distributions and projects are using CentOS as a basis for their software. These include: RocksClusters, Trixbox, SME Server, Boston University Linux, Strongbolt, and NuOnce Networks CentOS / Blue Quartz Installation CD.

4. The CentOS Project is a community based organization with many (currently 12) developers from all over the world.

5. The FedoraLegacy Project is using CentOS servers to host their content.

6. CentOS breaks down their content in to several repositories, to make it easy to stay as compatible with upstream as possible ([os / base] and [updates] repos), while also providing extra added content (i586 kernel support / XFS, JFS, ReiserFS file system support / upgraded system components, etc. in their [extras] and [centosplus] repos) for users who want it. See this wiki entry concerning the CentOS Repositories.

7. CentOS provides a Cluster Suite and Global File System [csgfs] repository that contains a rebuild of that outstanding upstream product. (More information about the RHGFS and RHCS).

8. The CentOS website traffic as measured by Alexa.com (ranked 10,552 at the time of this article), is on par with several mainstream Linux distributions. These include Slackware (38,912), Mandriva (20,055), Ubuntu (62,461), PCLinuxOS(63,043), Knoppix(55,861), and DamnSmallLinux(34,659). CentOS is still lower than the biggest Linux distros Fedora/RedHat(2,160), Debian (1,943), Novell(3,517), Gentoo(2,977), but the other rebuild projects listed above are not even close to the CentOS numbers. Here are the other listed rebuild projects Alexa rankings White Box Enterprise Linux(676,588), Scientific Linux(no ranking), Lineox(1,340,799), Tao Linux(1,466,354), xOS (6,849,702), PieBox Linux(2,277,582), StartCom Linux(215,241).

9. CentOS has a huge number of public mirrors that provide updates for users. At the time of this article it was 130 mirrors all over the world.

10. A GeoIP based update system was developed by CentOS to provide a fast and geographically relevant list of servers for updates. This system allows for fail over and the optional fastest mirror yum plugin allows the mirrors to be tried in connection speed to your location. Two major releases with this update system have resulted in fast updates for more than 1.5 million CentOS machines that are installed throughout the world.

For all the above reasons, CentOS is the clear choice for a free Enterprise Linux solution.