Fedora stops supplying you with any updates after ~1.5 years, RHEL (and theoretically CentOS) will support you for 10 years. Not only this but the software gets through extremely vigorous QA, certifications etc, unlike Fedora (and many other distros).
Fedora is the development workhorse from which RHEL versions are spawned and hardened.
In short, want to run a mission critical application for many years? Go RHEL (or CentOS if you do not care about support and extra bits or cannot afford it). Want more bleeding edge stuff and faster paced development and updates? Go Fedora.
I use CentOS over Fedora because it's very stable and has a great support. Most distros that I've used crushed on me, fairly frequently compared to CentOS. CentOS and RHEL just seems very polished to me. I do run it as desktop on one of my machines but it's more of a server distro. I like Gnome2 too and I can't stand Fedora's Gnome3, it just gets in the way. One major draw back is software updates, they are a bit behind. But for the server I think its excellent. I'd compare Ubuntu to Fedora and CentOS/RHEL to Debian. Come to think of it, you can have extra repos on CentOS, like rpmforge and rpmfusion for newer software. I personally like CentOS.
CentOS is one of many distributions built from RHEL sources.
You use RHEL or it's derivatives for a series of reasons which all orbit around the same theme: supportability.
Red Hat works with major software and hardware vendors (especially 'enterprise' software and hardware) and with that you get official support between OS/Software/Hardware.
Red Hat releases stay viable for years and years so that the software you write will keep working with the same OS for years and years – OS updates won't kill software that used to work, and the setup you create will continue to work for quite a long time.
Red Hat keeps on top of security problems, fixes them quickly, and tells you about them in a professional manner.
Rogue hackers, brand new start-ups, and the like are very often much more interested in the latest and greatest thing and _not_ the long haul. Red Hat is conservative with what's new and popular focusing instead on maintainability and supportability.
Because it is essentially redhat without the license fee. If you are in enterprise space and all that vendors certify for their software is RHEL, chances are very high it will work well on CentOS.
My understanding is that CentOS essentially takes the RHEL packages and removes the trademarks (the RH logo and name).
Entirely legal and ethical under the GPL, and RH benefits from all the folks who know the RHEL system because of exposure to CentOS - when they're recommending a supported version of Linux, it's likely to be RHEL.
I think if CentOS were selling support contracts, that would be pretty bad. RedHat makes their money on support contracts. By using CentOS, you're more likely to switch to RedHat when you need to pay for a bunch of support.
It feels a little bit more moral to load CentOS on a bunch of systems, than to load Red Hat on them and only pay for one support contract. As an analogy, Microsoft probably prefers people to pirate Windows than to switch to Linux/Chromebook.
It's been a while since I looked, but I believe a few CentOS developers get paid by redhat, or if not, at least have alternate @redhat.com addresses. My impression has always been that CentOS and Red Hat have a good enough relationship that CentOS would not want to jeopardize that. Additionally, Red Hat benefits from having one of, if not the most common server distro (the numbers are hazy) based on their product.
The truth is, Red Hat is the only linux distro I can think of (besides maybe SuSE, but I don't know much about it) that has really made a significant push to take over the enterprise market from Microsoft (and now they've moved to trying to do the same thing to VMWare).
They simply repackage and rebrand RHEL, then give it away for free. If anything I'd be quicker to call RHEL the free rider on the hundreds of pieces of OSS software they use (but I do not make that argument).
If you want a warranty/support contract, definitely purchase RHEL. If you don't need that, but want enterprise grade stability and compatibility, use CentOS. If you want to run Linux on your laptop, don't use either.
> If you want to run Linux on your laptop, don't use either.
Actually CentOS 6.4 has been the most reliable thing on my Lenovo T61, T400 and Dell T3500. Everything works from hibernate, sleep, WiFi, SAS, SSD's out of the box with no configuration.
This is the polar opposite of Ubuntu, Debian stable, Debian testing and Mint which are royal bastards to get off the ground.
Never again. Always seemed laggy. I just loaded Scientific Linux 6.3 on 3 old thinkpads this past weekend. As you said, everything works. No "sudo vi /etc/X11/xorg.conf", no modprobe & ndiswrapper. Red Hat was my first peek at linux, so I'm a tad nostalgic (remember 9.1? crux, luxi sans?).
That's good because given the amount of code Red Hat contribute back to the community, including buying proprietary tools and open sourcing them, you'd look like a complete idiot.
Note that Oracle is/was doing the same thing (repackaging RHEL) with "Unbreakable" Linux, and they are selling support for it.
They also offer their "own" kernel.
The problem with Fedora is that it is bleeding edge - and can be a bit unstable. So they let things go into Fedora, wait a year or two for it to stabilise and get the bugs worked out, and then it goes into RedHat/CentOS.
That is, at least for major versions of software - they constantly update packages with security fixes that might come out, and continue this for years. This means even backporting security fixes from newer releases.
So you use CentOS when you don't mind packages being a little old, but want a very solid system with long term security updates (and there are the Software Collections coming out which let you get newer versions of certain things - like Postgres which is still 8.4 in the stock install)
Documentation is unsurpassed, it's very fast, it's pretty light weight, supported for a decade, stable ABI, completely hassle free, good OOB configuration, good 3rd party package support, available everywhere.
