Why is solaris preferred over Linux in most mission critical environments ?

What makes people choosing a professional instead of an amateur for a serious business ?

OK right solaris is more professional but what makes it so ?

Well, Gnu/Linux is viewed, sometimes (often?) with reason, by mission critical administrators and decision makers as an amateurish, unreliable, unstable, difficultly maintainable and poorly supported piece of software ...

I am not sure it true these days to say that Solaris is the OS of choice in most mission critical environments. I am sure if it was, it would not be rapidly losing market share to Linux and othe Unix like OSes. The truth is that Solaris can be easily replaced by Linux or BSD in most production environments.

I am also not sure that jlliagres comments above are right. If GNU/Linux is all that you say, how come there are many mass migrations to Linux and quite a lot of them are at the expense of Solaris.

I didn't wrote that, nor the OP. However, mission critical environments is certainly a place where Linux presence is pretty light while Solaris is high.
Is it ?
More than 3.4 millions Solaris 10 systems registered this year seems to me not what is called a market share drop.
Sure it can often be replaced by Linux, but this is not without risks, and mission criticals managers do not like risks.
Linux is lacking many requirements these applications are demanding.
Several of them are not applying to BSDs though, but application availability is one of the areas hurting BSD.
Are there ?
I do not see that, but well, perhaps if migrations do happen sometimes, one of the reasons would be GNU/Linux good marketing.

Your English semantics may differ from mine. I was merely rephrasing what the original OP was insinuating in their first post.

And how many Linux installations have there been this year? Its difficult to quantify.

I am not really a Solaris expert, but it would be interesting if you could point out some of these risks of using Linux and the features that it lacks which makes Solaris a better OS than Linux in critical environments (This will obviously benefit the OP as well).

I agree with you about the BSDs lacking applications, which limits its adoption in enterprise environments. As for Linux migrations, I am not sure how you have not noticed, when its always in the media that Linux is becoming the OS of choice in many enterprises and is rapidly replacing Solaris and other proprietary Unix OSes.

As a non native English speaker, I'm certainly doing mistakes in that matter.
To clarify my answer, I was just pointing out that the OP was writing (not insinuating) Solaris is preferred to Linux in this area. You rephrased that in "Solaris is the O/S of choice" without mentioning Linux, which is in my understanding a wider affirmation.
What may be the reality is that neither Solaris nor Linux are the O/S of choice in mission critical environments, but perhaps AIX, HP-UX, mainframe O/Ses or why not even Microsoft's Windows.
Correct, so you have no metric to assert Solaris is loosing market share.
Something sure is that Solaris adoption was boosted by Solaris 10 release, especially in the x86/x64 market.
You are welcome to become one.
I'm not talking about features, Linux is usually not lacking features, it tends to have plenty of them.
What Linux is lacking is reliability under intensive stress tests (high workloads, long run tests).
Also, Linux has no commitment in ABI stability and thus is difficult to maintain and upgrade, comparing to Solaris upward compatibility guarantee and patching policy.
Another area is the Linux poor observability, especially when comparing with Solaris 10 dtrace, but even strace is very weak when compared to truss.
This exactly what I was calling "good marketing", the media.
I'm not living there but in datacenters and IT departments where the reality is different.
Please don't misinterpret what I wrote, I do not pretend Linux doesn't exist and has no presence nor future in the enterprise, but the OP was talking about mission critical environments, not general purpose applications, for which I'm happy to see Linux and FOSS software are gaining market shares, like desktop's Open Office, Firefox, Thunderbird, Apache Tomcat and the likes.
By the way, I'm not sure how you have not noticed, but Solaris is now an OSI compliant Open Source and Free Operating System, not exactly what "proprietary Unix" insinuates.

Mmmm, saying BSD and Linux aren't used in mission critical environments isn't real. If you want Solaris stability install it on Sun's hardware, it's nowhere near strong as Linux on Intel... Also, you must be willing to substitute many of the Sun's binaries with GNU versions if you want to get the robust ones. Solaris and the BSD's are the best 64-bit OSes, but I prefer the latter as off_t (for example) is 64-bits wide and there's no need for you to handle fstat() vs fstat64(), for example.

What makes Solaris good is that's strong, one (not fragmented as Linux, I hope Sun's version will take precedence over new experiments), well tested and very well documented. DTrace rocks. It's being implemented in FreeBSD. But we're seeing universities and ISP's migrating from Solaris & OSF/1 to Linux or FreeBSD, and we see IBM happy supporting Linux as well, so where's this "amateurish" myth?

I agree, and I didn't wrote that in this thread, the discussion was about preference.

This is misinformation, Solaris code is the same regardless of the target H/W. The low level assembler has certainly no impact on stability. And Sun hardware includes x64 hardware anyway.

You are confusing number of features with robustness.
Standard utilities are guaranteed to be compatible with previous ones with Solaris, this what mission critical users are expecting, not ls fancy colors.

Solaris is just easing the ISVs task by providing a transitional interface.

True, BSD license allows Solaris code reuse in its kernel, easing this interesting work.

I never contested that, but Universities are not good examples of mission critical environments. ISPs are seldom using linux for their core critical tasks, like billing.

One of the reasons explaining Universities Gnu/Linux adoption was Solaris previous licensing (closed source, source licence forbidding code change). This is no more true with OpenSolaris, and anyway has nothing to do with this thread.

Not sure if IBM is really happy, but IBM is certainly still recommending z/OS, OS/390, MVS and AIX for mission critical tasks, instead of Linux.

Gnu/Linux amateurism is not a myth, its development model is designed that way, and I don't say it's all negative, just it doesn't fit the mission critical needs.

Mmmm, saying BSD and Linux aren't used in mission critical environments isn't real.
So, what was your answer to the original question?
Should I have said this?: "Mmmm, saying BSD and Linux aren't as used as Solaris in mission critical environments isn't real". I've seen Solaris used more in workstations. Linux is not an amateurish thing, there are professionals from a wide margin working on it and it is even broader in the case of GNU/Linux. One thing that I like about Solaris and *BSD is the integration of binaries and libraries into the base system, something that has been achieved by Debian anyway.

It's not a secret that they support more their own hardware. This is what preference make come into play when deciding for the best OS that would run on a particular hardware.

No. I did say robustness. GNU software is known to be coded in such a way as to make it handle any type of input. This is no myth that everyone can check. The only thing that I really hate about GNU is the coding style.

And what is this support coming from many players of the Unix camp: IBM, Sun, SGI, Novell (owner of some Unix rights), etc ?

They're promoting software for their own hardware. They would never create an emulator on top of it to support Linux, should they? This is why it's really an issue this hardware thing. NetBSD, for example, runs on many platforms that FreeBSD may never support because many of the innards, design criteria and services provided by the OS can't be easily integrated into new hardware.

What the major players mentioned above sell is precisely this mission-critical propaganda and they're all playing with GNU/Linux, so where's this myth from?

My answer was, and still is:
Well, Gnu/Linux is viewed, sometimes (often?) with reason, by mission critical administrators and decision makers as an amateurish, unreliable, unstable, difficultly maintainable and poorly supported piece of software ...
Well, a double negation is overkill, but yes, this sentence has a very different meaning than your previous one, and indeed I disagree with it (making a triple negation, sorry ...).
You are also adding BSD in the discussion while the OP was discussing Linux and Solaris.
I'm seeing it used more on servers, and often on mission critical projects, so our experience differ. It is no surprise, as I am a Solaris O/S and Solaris application specialist, while you seems to be more a BSD one.
I do not contest that, including Sun engineers are certainly working on Gnu stuff too. I'm not arguing about the people but about Linux design and model vs Business Critical requirements.
Of course, as a hardware vendor, Sun is supporting its boxes, just like Dell/HP/IBM and any other are supporting their.
The hardware quality/reliability and the support quality is one of the parameters helping users to make their decision.
You are also correct about the link between hardware and O/S, of course Sun is investing more in supporting its own devices .
This is an area where Solaris has an advantage over Linux, Solaris supports live-upgrade, native FS supports snapshots, High-end Sun hardware supports hot swapping almost everything, including disks, i/o boards, CPUs, memory, power-supplies.
The O/S has support to seamlessly put off line components like CPU and memory as soon as they start to be faulty (predictive self healing), where is Linux there ? These are thing that do matter on business critical environments.
You are also contradicting yourself, you first tell Solaris is not doing well on Intel hardware then you tell Sun runs better on its hardware.
How do you concile that with the fact Sun hardware does includes Intel architecture (AMD64 precisely) boxes ?
Whether this is true or not, mission critical applications are anyway usually non Gnu but mostly home made or proprietary, and are less in a situation where unexpected input happen.
Again, it's not the support which is or not professional, it's about design.
Not sure of the point, IBM is certainly supporting an "emulator" to allow running linux on top of a virtual machine.
SUN's lx Brandz is also about creating a layer allowing to run Linux applications unchanged on top of Solaris.
Contrarily to IBM's solution, Brandz doesn't lock users to proprietary hardware, it runs on any Intel or AMD based machine.
I'm not familiar with these FreeBSD/NetBSD differences, but they certainly have nothing to do with a Linux vs Solaris on business critical applications discussion.
Well, "playing" is perhaps the right word ... and mission critical is not about playing.

This is the root of the matter here. Please explain every adjective with truths rather than hyperboles and/or strong words.

Man, I've been working on migration solutions from propietary OSes (in many cases Solaris, which is not the case now) to both Linux and BSD's. And the reason wasn't always licensing costs, both ease of administration (Solaris is a behemot). Every service that was running on Solaris (NFS & NIS a few years ago), runs perfectly on these OSes. There has never been a problem with them. Upgrading any piece of library on it for security reasons is easier on these systems than Solaris. Trusted Solaris is not easy to get straight. Is it still supported?

What is this model that seem amateur to you?

Well, Intel isn't Sun's hardware as much as it isn't Apple's, but the fact that it's included says something. I'm still not happy with performance on x86.

These companies cannot "play" in any sense of this word. The fact that they're contributing to Linux is what is meaningful to me, and this is serious. No words-play here.

For SGI contributions see:
http://oss.sgi.com/projects/
See specially:
http://oss.sgi.com/projects/failsafe/

Sorry, Jlliagre, this is off topic, but I didn't understand your comment about the BSDs and applications. Are you saying the BSDs (including FreeBSD with its huge ports collection) are lacking in applications as compared to Solaris? Looking at what's available from Sun and from sites such as Blastwave, I got the opposite impression.

I'm not saying that.
So do I, Solaris still need work to have as much binaries available as Linux/BSD FOSS do.

My answer was only related to business critical applications, which are usually not
FOSS, but proprietary ERPs, databases and Application Servers. These are domains where big players support (eg. IBM and Oracle) made Linux viable.
BSD is unfortunately lacking this kind of support.