The Clone Wars – CentOS vs. Scientific Linux

Update: The conversation continues HERE.

With Linux in the Enterprise, RHEL is king. Sure there are people who love and use Debian, or Suse. I would imagine that if you looked hard enough you could likely find somebody who’s using Slackware or Gentoo in a business somewhere. But I think it can safely be said that RHEL is currently the dominant enterprise Linux distribution. Then, of course, there are the clones.  If you so choose, you can forgo Shadowman’s Support team and either compile the freely available Redhat Source RPMs, or choose to use a community-supported RHEL clone. Currently, the two most popular of those clone distributions are CEntOS (Community Enterprise Operating System) and Scientific Linux (SL).

So if you have decided to not utilize Redhat support, which of these downstream clones is the better choice? With the recent (much delayed) release of CentOS 6.0 in the past week, many companies are looking to move up to the RHEL 6.0 family of operating systems. But is CentOS still the right choice? Being a primarily CentOS shop, and being more than a little OCD myself, I decided to compare the two in as practical as a manner as I could. Below are the results.


When it’s running on production, you don’t have time to wait on a tiny community to figure out how to backport in some obscure cross-site scripting vulnerability in an even more obscure module in your favorite language, even if you’re part of that community. An enterprise operating system needs to have an active and robust community to support itself, paid or not.

CentOS has been around for a long time and has a huge following. There have been murmurs of late about the core contributors getting tired, and the delay in CentOS 6.0 was the evidence. I don’t believe that fully, but I do believe the project could do with some fresh blood and possibly some new ideas.  But I don’t think it’s going anywhere anytime soon.

Scientific Linux hasn’t been around nearly as long, at least on the scale that it is currently enjoying. The community, however, is vibrant, and is backed by several large research labs such as CERN and Fermilab. Big plusses.

Advantage: Push


In Open Source software, the process is often times as important as the product. While I don’t believe there is anything massively different in how these 2 projects are doing what the do, SL is certainly better at talking about it and making the community aware of how it’s working. This presentation(PDF) is a pretty great one, even if it’s a little dated. SL Community, I’d love to see an update, for the record.

Advantage: Scientific Linux

RHEL Compatability:

This used to be a much larger difference, as late as version 5.x. Scientific made some pretty large changes to the RHEL repository structure, and added in some packages of their own. CentOS has always been as faithful a clone as was possible at the time. This is largely cleaned up in version 6.0, with the extra SL packages moving out to external repos, but much like the workflow advantage above, perception is still a strong influence.

Why is this important? Well, like lots of people, we’re a mixed RHEL/CentOS shop. It just makes life SO MUCH EASIER.

Advantage: CentOS

Mirror Speed and Availability:

I couldn’t find any perceivable difference in this category. Both networks are robust and highly available.

Advantage: Push

Community Support:

This is one of the most important factors when adopting a distribution, and sadly the one answer I’m not able to fully answer. I utilize CentOS support all the time, via the web, forums, and IRC. I’ve only occasionally sought support for SL, and this was way back in version 5.2. So I’m not really qualified to answer this one fully right now. However, I see active forums off of their home page and a 10 minute visit to the IRC channel on freenode saw plenty of conversation for a Tuesday night. I don’t think SL would have grown so much without good community support.

Advantage: Push

Lifecycle Support:

This was the one that surprised me.

As expected, CentOS mirrors the RHEL lifecycles. RHEL/CentOS 5.x will be supported through 2014. They haven’t updated their wiki yet, but I’m sure 6.x will be the same, with a full 7-year lifecycle.

Scientific only plans on a three year lifecycle. But on their forums they also mention supporting things in theory as long as Redhat does. So I’m a little confused on this one.

While I don’t typically plan on using the same OS for longer than 3 years, if it ain’t broke, I’m certainly not fixing it.

Advantage: CentOS

So those are my thoughts on the situation. Scientific Linux is definitely on the rise, and CentOS certainly needs to air out themselves a little. But at least with version 6.0, we’re still going to be going with our tried and true CentOS. I’m just not comfortable enough, yet, with the Scientific Linux community, mainly because they still don’t quite know how long they plan to keep their products alive. Out of this look at RHEL clones, though, the single biggest thing I’ve discovered is that I’m going to have to keep evaluating this choice down the road.

25 thoughts on “The Clone Wars – CentOS vs. Scientific Linux

  1. i followed your 3 year life cycle link ( which is actually their “future of SL” page), that’s from 2005. It in turn links to the actual lifecycle page. that one clearly states that 6.0 will be supported at least until 2016-11-11. and 5.x at least until 2014-03-02.

    they also say specifically that they cannot “guarantee” anything because:
    One of the possibilities is that the source rpm’s from the Enterprise release will
    become unavailable.

    which is a quite reasonable observation ( as we can see from RHEL recent kernel policy change ). Are making more out of this than is actually there?

  2. If they haven’t revisited their “Future” page since 2005, I think that speaks to a certain lack of maturity in and of itself. That is a top-level link inside their documentation, and has what is at best misleading information on it.

    I know it’s a volunteer project, but if I’m going to use a distribution as a solution that I’m going to sell to my bosses, then the documentation had better be more up to date and/or more accurate.

    again, all my humble opinion.

  3. CentOS took over half a year to deliver CentOS 6, and has yet to deliver their “continuous” repository for security fixes offered in CentOS 6.1.

    They keep the build process opaque to the world, and do not loudly show the progress of the process on their site.

    Under the contributions section of the CentOS site, there is no place to volunteer for progressing the actual CentOS system.

    CentOS needs to be replaced by a transparent, truly open, and willing community.

  4. I’ve been a fan of CentOS for many years. But their closed and slow process of releasing CentOS 6 was a big disappointment. They could not even be bothered to keep the community informed about their progress (or lack of). Sadly, CentOS no longer seems reliable.

    People wanting to invest time and energy in a RedHat clone will turn to Scientific Linux. The Scientific Linux community is more open and welcoming than CentOS. And they release new versions twice as fast! The backing of major European scientific organizations is certainly a plus. I’m glad that Scientific Linux is growing stronger just when CentOS is fading!

  5. We’ve used CentOS in a production environment since 2004. Like others, we’re disappointed in the delay of CentOS 6, and the lack of information surrounding its development and release. As e needed to refresh hardware, and the CentOS versions on it, we sought alternatives. We did look at Scientific, but weren’t overly impressed with it. We was recently introduced to PU-IAS, Princeton University’s RHEL clone entry. The PU-IAS Web site touts this distro as pre-dating CentOS. We’ve installed it, we like it. PU-IAS seems to be a well kept secret that’s worth a look.

  6. After spending a few hours installing CentOS 6.0 under VirtualBox, I have to say that I am *very* disappointed in this release. The networking is just a mess, with heavy dependencies on NetworkManager in profiles such as “Basic Server” which makes no sense.

  7. I have probably stepped into waters into which I will drown, but I installed CentOS 6.0 onto a refurb PC I bought. I have been using Ubuntu, on my everyday PC, since 2007 and run their LTS (Long Term Support) releases. I have SOME experience of the CLI and with text files but am NOT a Sys Admin.

    The upcoming Unity desktop in Ubuntu is a deal breaker for me. I installed LXDE and am hoping Ubuntu 12.04 LTS does not break that.

    I do not need bleeding edge, so it was Debian Stable or CentOS for me on the refurb. All the default apps are fine for me and I have no external devices (printers, scanners, cams, etc.). I just have to find updated instructions for 6.0 for plugins (java and flash) and I should be done.

    Thanks for the article; which, by the way, I found as a link on Distrowatch.

  8. I’m just wondering, have you seen that Ascendos project that’s just starting up? They seem to be a force promising a more community-oriented “generic” distribution that could also be used as a common base for these clones.

  9. Hi Jamie…it’s John from the SLF. I appreciate your article, but SL has the same life cycle as RHEL. The lead programmer for SL is Troy Dawson. You should email him and ask about ABRT, or rather the lack of it. Bugs are reported on the Official Mail List, and usually handled rather quickly. I’ve been using Scientific Linux 6 x64 since February of this year, and have never had any quirks, crashes, or odd behavior. It’s been solid. This after adding all codecs, etc from the EPEL, ATrpms, ELRepo and RPMForge repos. We’re lucky to have it. My CentOS experience goes back to 5.5, which I had to uninstall due to oldish kernel issues. SL 6.1 will be out in roughly a week.

  10. PS: Ascendos, a new RHEL clone is being worked on and looks very promising. 🙂 The more, the merrier! The SL community is heavily involved in this project as I am subbed to the developers mail list.

  11. Their site indicates support for SL6 and 6.1 until 2017

    The fact they rolled out 6.1 quickly was a factor in my choosing SL between the two to run as a desktop. From everything I have read they both work equally well in that function. There may be differences in running a server, something I can not address.

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