Maybe... but the companies buying support contracts and sending real dollars RedHat's way are going to be mostly the big shops, the enterprise shops, and I've never seen ubuntu-server in an enterprise shop.

What's an enterprise shop? I've worked at a big public company that used ubuntu-server.

US Army (2007): “When we rolled into Baghdad, we did it using open source. It may come as a surprise to many of you, but the U.S. Army is ‘the’ single largest install base for Red Hat Linux. I'm their largest customer.”[1]

[1]: http://web.archive.org/web/20110521185400/http://www.linux.c...

Baghdad is cool, I guess, I'd rather go to the space station with Debian:

http://phys.org/news/2013-05-international-space-station-lap...

Isn't "General Justice" a great name for a superhero?

U.S. Navy uses Red Hat too, though perhaps not to that same extent as the Army.

That's because the US Army is still fighting the cold war, and thought it was "Red Hate Linux".

One that values support from companies like Oracle, is a good first approximation.

If you define an enterprise shop to mean a company that doesn't use software like ubuntu-server, congratulations, you are right, but you have also made a completely meaningless observation.

Well good thing that I didn't define it tautologically like that then.

Instead, I suggested - as did your parent comment - that support contracts are very important to "enterprise" shops. That can be considered a defining characteristic in so much as nebulous terms have defining characteristics. And if you don't understand the importance of those support contracts, a lot of their behaviour will appear strange.

It's simply a fact that a lot of these companies officially support RedHat, often Suse, sometimes CentOS, but rarely so far for Ubuntu Server. That may change, but Ubuntu is definitely not there yet.

Ok sure, that makes sense, if the qualification is SLAs and the like. I bet RedHat dominates in that case.

Support isn't just about SLA's, its about your vendor actually providing software/drivers/etc for your environment. I think you will find many commercial applications only support recent versions of RHEL, SLES or in some industries Oracle Linux.

These products don't ship with source code, and they tend to fail spectacularly when put on machines that don't happen to have the "right" kernel, library and system tools. Frankly, having shipped binary products on linux in the past, it can be a real PITA just maintaining an application over three or four versions of RHEL or SLES (which have a lot more in common with each other than they do with debian based distros).

Two random links to prove my point:

http://www.3ds.com/support/certified-hardware/simulia-system...

Random hardware link:

http://driverdownloads.qlogic.com/QLogicDriverDownloads_UI/D...

I don't have a formal definition, but in my head "enterprise" is somewhere around the "10,000+ headcount" line.

I of course have only worked for a few enterprise shops; my evidence is purely anecdotal, and I know that.

An important part of the equation though as to how much this matters to Canonical or RedHat; was this shop you worked in paying for a support contract?

(Support contracts are perhaps not a defining feature of "enterprise", but they are a common theme)

Enterprise is where the people who choose the software don't use the software. Software is sold there not bought.

Canonical made around $50m revenue last year (and lost $20m). RedHat made $1.5 billion and was profitable.

It's a pretty big difference!

That does not address the above comment. Just because they aren't getting money for the installs does not mean that ubuntu isn't being used as a replacement for RHEL.

CentOS and Scientific Linux are used as replacements for RHEL.

It addresses the 'buying support contracts' part.

Depends... do they pay Canonical for support?

If yes, then, yes, they're eating into RH earnings

Otherwise, it's a battle between Ubuntu Server and CentOS

Probably not much. If ubuntu didn't exist, most of those installations would just be some other free distribution.

I think your statement is more true of CentOS than Ubuntu. Many Ubuntu server installations choose it because it is free and reputedly easy, and pass up CentOS because it doesn't have a lot of selling points that appeal directly to non-Linux users, nor RHEL because it costs money.

Also your comment reminds me of an argument against stealing music on the Internet, lol.