[ceslami]

> if you get far enough and need to scale

Alright -- I'll bite.

Rarely anyone "needs to scale." Plenty of $1B businesses can succeed on a fistful of c4.large's running Ruby on Rails. The same Ruby on Rails that ran their MVP. Scaling via language change isn't the path to victory, unless you picked a language that was poorly suited to your domain to begin with.

Too many companies end up following this cargo-cult advice, and spend more time grappling with their tools than innovating. Because "concurrency." Someday.

Optimizing your choice of language for anything other than a linear relationship between Real Complexity and Implementation Time is a fool's errand and a fiduciary travesty.

In all fairness, Elixir/Phoenix could become as well-learned as Ruby on Rails. We'll end up in a best-of-both-worlds scenario. And at that point, I'll happily eat my words.

But in the meantime, solve your "scaling" problems by measuring and optimizing, instead of re-writing your app in the flavor-of-the-week.

[themartorana]

I can't think of a single billion dollar Corp that can run Rails on a few AWS boxes. Time and again companies have rewritten systems from MVP to handle data safer, better, and faster, from Dropbox to Twitch to CloudFlare to Uber to Mail.ru...

Then there are plenty of 7 figure companies that have also had scale issues. Game companies come to mind first and foremost but they're hardly the only ones.

You want to run your marketing website on Rails? Yeah of course. But billion dollar companies on Rails?

[ceslami]

For the sake of discovering a middle ground between our arguments, let's look at an example of a >$1B company running Rails: Github.

Most of Github's stack is Ruby on Rails, with specialized components/sub-systems written in C. This is a common theme amongst companies that use Rails or Python at scale.

There's a reason why people keep those languages around. Its the same reason why they tend to be used for MVPs: the tool gets out of your way so you can focus on solving the hard problems of your domain. The longer you can preserve those ergonomics, the better.

[vacri]

My guess is that Github uses a few more cpus than "a fistful of c4.larges" suggests.

[patkai]

I wonder about the valuation of Basecamp, they may almost qualify.

[rdtsc]

> Rarely anyone "needs to scale."

Agree, and I say it as an Erlang full-time dev. Chances are you don't need 9 9s reliability and super scalability.

I've heard and seen cases of companies rewriting stuff unnecessarily due to some incompetent people following latest fads. "Oh I read Python has the GIL so we need to switch to Go. Saw on HN everyone is switching" -- cue years wasted in rewriting and destabilizing a solid usable code base.