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Linus Torvalds on Why ARM Won't Win the Server Space (realworldtech.com)
Linus Torvalds: I can pretty much guarantee that as long as everybody does cross-development, the platform won't be all that stable. Or successful. Some people think that "the cloud" means that the instruction set doesn't matter. Develop at home, deploy in the cloud. That's bullshit. If you develop on x86, then you're going to want to deploy on x86, because you'll be able to run what you test "at home" (and by "at home" I don't mean literally in your home, but in your work environment). Which means that you'll happily pay a bit more for x86 cloud hosting, simply because it matches what you can test on your own local setup, and the errors you get will translate better. This is true even if what you mostly do is something ostensibly cross-platform like just run perl scripts or whatever. Simply because you'll want to have as similar an environment as possible.
Which in turn means that cloud providers will end up making more money from their x86 side, which means that they'll prioritize it, and any ARM offerings will be secondary and probably relegated to the mindless dregs (maybe front-end, maybe just static html, that kind of stuff). Guys, do you really not understand why x86 took over the server market? It wasn't just all price. It was literally this "develop at home" issue. Thousands of small companies ended up having random small internal workloads where it was easy to just get a random whitebox PC and run some silly small thing on it yourself. Then as the workload expanded, it became a "real server". And then once that thing expanded, suddenly it made a whole lot of sense to let somebody else manage the hardware and hosting, and the cloud took over. Do you really not understand? This isn't rocket science. This isn't some made up story. This is literally what happened, and what killed all the RISC vendors, and made x86 be the undisputed king of the hill of servers, to the point where everybody else is just a rounding error. Something that sounded entirely fictional a couple of decades ago. Without a development platform, ARM in the server space is never going to make it. Trying to sell a 64-bit "hyperscaling" model is idiotic, when you don't have customers and you don't have workloads because you never sold the small cheap box that got the whole market started in the first place.
Which in turn means that cloud providers will end up making more money from their x86 side, which means that they'll prioritize it, and any ARM offerings will be secondary and probably relegated to the mindless dregs (maybe front-end, maybe just static html, that kind of stuff). Guys, do you really not understand why x86 took over the server market? It wasn't just all price. It was literally this "develop at home" issue. Thousands of small companies ended up having random small internal workloads where it was easy to just get a random whitebox PC and run some silly small thing on it yourself. Then as the workload expanded, it became a "real server". And then once that thing expanded, suddenly it made a whole lot of sense to let somebody else manage the hardware and hosting, and the cloud took over. Do you really not understand? This isn't rocket science. This isn't some made up story. This is literally what happened, and what killed all the RISC vendors, and made x86 be the undisputed king of the hill of servers, to the point where everybody else is just a rounding error. Something that sounded entirely fictional a couple of decades ago. Without a development platform, ARM in the server space is never going to make it. Trying to sell a 64-bit "hyperscaling" model is idiotic, when you don't have customers and you don't have workloads because you never sold the small cheap box that got the whole market started in the first place.
I always found it strange to use an Ubuntu server. Whilst it's okay, and often better than most BSD or other systems, it's not as stable as RedHat. So why so many Ubuntu servers? It's simple: that's what the developers are using. Linus is, as occasionally happens, spot on with this one. If you can't get exactly the same set up locally there's always going to be the odd really difficult debugging case that just takes you too much time to justify. The solution is obvious: start providing ARM Linux laptops with very similar processors to the ones used in servers. I'll buy a few myself.
x86 won on price, on the desktop, on the server. That is the simple truth.
As for stability and bugs, cross platform is superior. Bugs that are hard to manifest on one hardware architecture may manifest quite readily on a different architecture. Having worked on various cross-platform projects I've seen the main x86 based dev teams visit the alternative architecture teams (ex PPC) when they are stumped debugging, they eventually appreciated the alternative architectures. A single architecture target allows for longer lived quirky bugs. The simple truth is that cost is more important to many.
This is not to say ARM will be successful in server space, just that it will be about cost and little else.
Motorola on the other hand seemed more willing and eager for PPC to catch on. It didn't work out but you did see some random machines adopt it for short periods. The BeBox, the half backed second chance at Amiga's, random accelerator cards for various obsolete machines etc. The best shot PPC ever had at getting wide adoption was during the short period Apple licensed Mac clones in the mid 90's. Jobs shut down when he returned. Regardless of whether that was the right move it did mean PPC would never be a serious contender to x86.
At some point in the near future, Macbooks will start coming with custom Apple designed ARM processors instead of Intel chips.
At that point, the trendy urban hipsters buying these Macbooks will be developing on ARM and will want to deploy their code on ARM based servers. Your local IT department might say no, but I'm sure that the cloud hosting providers will gladly oblige.