[ben_jones]

People forget that the two methods of scaling are HORIZONTAL and VERTICAL. They think: "I can just put some micro-services behind HA proxy and boom, more capacity!".

And then they forget if they had just modified that one query and tweaked that one for-loop they could've had that same capacity without launching six new servers with all kinds of potential for the wiring to go down and cause downtime. Plus the dev time to build the services.

[bane]

I usually think of scaling in 3 methods: horizontal (add more machines), vertical (get a bigger machine) and inward (improve your algorithms).

The largest performance gains I've seen are most often of the inward type -- like multi-thousands of percent, just by rethinking the code or the approach.

Bonus, improving inward scaling multiplies investments in horizontal and vertical scaling.

[aianus]

Vertical scaling requires hiring good engineers instead of mediocre ones (additional cost of $100,000s per year across the team). Horizontal scaling in comparison is much, much cheaper for your average CRUD app.

[brianwawok]

Maybe, maybe not.

For example choosing Java over Ruby would give you 2-10x better perf per server... and I am not sure that Java devs cost any more or less than Ruby devs.

Now we can get into an argument about developer productivity and all that.. but form a purely "i want to run 10x more users per server"... something like Java / Ruby gets you a long ways.

[joslin01]

I talked to a CTO once that said he brought his RoR fleet down from 60 servers to 6-8 by switching to Scala.

[matthewmacleod]

When he said "switching to Scala" I reckon he probably meant "rewriting our platform."

It's very difficult to do a comparison like this in practice, because switching languages inherently involves a rewrite of a platform.

[collyw]

I am curious how much a rewrite staying in Ruby could have saved. Its always easier to write code when you have a good specification, and a working application would fulfill that role well.

[FooBarWidget]

I was once involved in a large-scale government project that rewrote a Java app to RoR. They went from 50 servers to 10.

It has probably got more to do with the rewrite and the new architecture than whatever language it was written in.

[joslin01]

What? It absolutely has to do with the language.

Ruby binary trees: 57 seconds Scala binary trees: 11 seconds

[1] - http://benchmarksgame.alioth.debian.org/u64q/ruby.html [2] - http://benchmarksgame.alioth.debian.org/u64q/scala.html

[FooBarWidget]

That would mean something if Ruby apps are 100% Ruby and/or are performing binary tree operations all the time, or doing similar kinds of CPU-intensive operations as depicted in the alioth benchmarks. But they don't. Ruby web apps perform lots of string manipulation, memory allocation, I/O. A lot of expensive things are offloaded to C libraries. Things like XML parsing are offloaded to native libraries like libxml; nobody uses an XML parser fully implemented in Ruby. Ruby does not reimplemented gzip compression in Ruby, it uses zlib. So the alioth benchmarks are not representative of real-world performance.

[wstrange]

Or the fact that new servers are an order of magnitude faster than the ones they replaced.

[Drdrdrq]

Order of magnitude faster? I doubt that. Unless the old ones were really old / slow to begin with. But really, we are both speculating without knowing the facts.

[aianus]

> I am not sure that Java devs cost any more or less than Ruby devs

I don't know about that, how many bootcamps are pumping out Java programmers instead of Python/Ruby programmers?

[brianwawok]

Well in Chicago some of the colleges are pumping out Java Devs...

I guess if you are comparing a 4 year college Java dev to a 6 week bootcamp Ruby dev you have something, but that seems weird...