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How Discord Scaled Elixir to 5M Concurrent Users

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Re: How Discord Scaled Elixir to 5M Concurrent Users

#231

Post by lod723 »

cooervo wrote: post #184
iagooar wrote: post #19

This writeup make me even more convinced of Elixir becoming one of the large players when it comes to hugely scaling applications. If there is one thing I truly love about Elixir, it is the easiness of getting started, while standing on the shoulders of a giant that is the Erlang VM. You can start by building a simple, not very demanding application with it, yet once you hit a large scale, there is plenty of battle-p…

Truly the strenght of elixir comes for Erlang. I wonder if Scala is also as good as erlang for creating robust and fail proof distributed systems?

No, because the JVM currently lacks features to truly isolate threads of execution, which is important for both performance and reliability. AFAIK, the JVM folk aren't even talking about addressing this, which is disappointing.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#232

Post by awj »

zild3d wrote: post #213
agentgt wrote: post #200

Earlier quoted context omitted.

> while my Java apps take 2 minutes to start up This is the classic case (and I'm/we are guilty of it as well) of Java apps that are probably traditional monolithic apps that use frameworks with extensive reflection and class loading (ie spring component scanning). You can get ridiculously fast loading time with Java if you use Dart2, a reasonable web framework and no ORMs. I'm talking 500ms... sort of depends on you…

500ms is not "ridiculously fast".

For service startup time? Sure it is.

How often are you booting your webservers that 500ms isn't fast enough?

Re: How Discord Scaled Elixir to 5M Concurrent Users

#233

Post by joshbaptiste »

zild3d wrote: post #213
agentgt wrote: post #200

Earlier quoted context omitted.

> while my Java apps take 2 minutes to start up This is the classic case (and I'm/we are guilty of it as well) of Java apps that are probably traditional monolithic apps that use frameworks with extensive reflection and class loading (ie spring component scanning). You can get ridiculously fast loading time with Java if you use Dart2, a reasonable web framework and no ORMs. I'm talking 500ms... sort of depends on you…

500ms is not "ridiculously fast".

in the JVM starting world it is..

Re: How Discord Scaled Elixir to 5M Concurrent Users

#234

Post by cutler »

di4na wrote: post #172
cutler wrote: post #11

Earlier quoted context omitted.

Despite its appeal to HN geeks I doubt if Elixir will ever achieve mainstream adoption. Searching Indeed.co.uk's API by title, there are only 5 Elixir jobs in London, compared with 445 Python and 171 Ruby. I also attended a Silicon Roundabout jobs fair recently and was disappointed to find Elixir wasn't even listed in the literature.

Just saying but most companies that search elixir dev do not go in this website. They immediately go for the community. Faster, easier and you get more consistent results. Difference between hiring "someone that knows it" and "a good dev interested by it"

That's probably also true of Ruby and Python re hiring so the numbers are still relevant.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#235

Post by jlouis »

majidazimi wrote: post #206
jlouis wrote: post #197

Earlier quoted context omitted.

Erlang (and by extension Elixir) definitely provides a set of tools which are good for building highly concurrent distributed systems. And your systems are likely to have few errors as well as being resilient, if you know what you are doing. But indeed, you need to know your tools like every other part of computer science. Storing 9 billion elements in an array, doing linear search and then complaining your linear se…

Consider for some reason (either technical or political), this company decides to migrate their web socket servers to Akka/Rust/Go/NodeJS. Integrating these new servers into their core cluster is going to be deadly painful. They rely heavily on Erlang/OTP internal clustering. This is not even considered as a challenge in distributed systems but still really painful to implement because of their design decision. This…

It isn't that hard. I have code which lets an OCaml program speak the Erlang distribution protocol. It can more or less stand-in for an Erlang node in the distribution layer. Writing the same for another language shouldn't be that hard: the protocol spoken is a simple prefix-protocol which can be parsed with LL(1) from the head plus an atom cache that is easy to maintain.

That said, good Erlang architectures definitely knows when you should fan out and use a common layer for distribution. At $work we have a Kafka cluster for some event handling simply because it is the right tool for the job, and because it makes it easier to interface other programs on top of it.

In my experience, the distribution features are best used as orchestration however. Your distribution layer is Erlang, and then you use other languages for "leaves" in the architecture. If the right library is present in e.g., Go, then by all means use it. Erlang easily speaks protobuf for instance.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#236

Post by mahyarm »

aphextron wrote: post #142
jakebasile wrote: post #39

Earlier quoted context omitted.

If there was an open source and federated equivalent to the features Discord provides I'd use it. There is no such product. Matrix is interesting, but the experience is no where near as polished as Discord and friends and that matters for mass adoption.

>If there was an open source and federated equivalent to the features Discord provides I'd use it. But will you pay for Discord though? The features and quality Discord is able to provide are artificially propped up by VC funding. When it runs dry, we will be left with open source offerings, or the next product to take it's place and repeat the cycle.

I would if they made the corporate / generic edition ;) It's better than slack

Re: How Discord Scaled Elixir to 5M Concurrent Users

#237

Post by tormeh »

justinhj wrote: post #219
cooervo wrote: post #184

Earlier quoted context omitted.

Truly the strenght of elixir comes for Erlang. I wonder if Scala is also as good as erlang for creating robust and fail proof distributed systems?

Scala paired with Akka is definitely good for that, I don't know how it compares performance wise with Elixir, would be interested to know. We're building a game server backend with lots of messaging in Akka.

Scala/Akka is a lot faster than Erlang, but it also lacks per-actor GC, which means that latency is going to be higher in a Scala/Akka system. Also, the per-actor heaps in Beam means there's no risk of two Erlang actors having a reference to the same memory, whereas that's easy to do in Scala/Akka.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#238

Post by tormeh »

Vishnevskiy wrote: post #119
jjirsa wrote: post #113

Earlier quoted context omitted.

Two things are true about Cassandra: It is by far the best at doing what it does It has plenty of room for improvement

You are 100% right that it is the best at what it does. And thank you again with helping us with that bug :) we really appreciate it.

I'm currently far down the database rabbit-hole and have to ask: What's so great about Cassandra that you can't get with CouchDB or other AP (yeah, I know...) databases?

Re: How Discord Scaled Elixir to 5M Concurrent Users

#239

Post by di4na »

mononcqc wrote: post #187
di4na wrote: post #170

Earlier quoted context omitted.

The problem is not and has never been the syntax. It is the tooling. No build tool. No way to generate a new project. Do it yourself docs. No templating system. Macros ala C. No package manager. Building releases was a dark art. It is now getting better. But it was a really steep curve to adoption.

Aside from macros, pretty much all of these have been covered by build tools for a few years now.

I know but iirc your own talk on tooling "we had to steal elixir package management to get one"

Re: How Discord Scaled Elixir to 5M Concurrent Users

#240

Post by toast0 »

smokeyj wrote: post #221
cdegroot wrote: post #118

Earlier quoted context omitted.

That, indeed. When I compare Elixir/Erlang to some other systems I worked on, "shallow" is the word that pops up. You hit a limitation, you dig into some source code, and you find out that it's pretty simple to understand and to fix it. It feels manageable, I've yet have to run into frustrating roadblocks, and that all gives me the confidence that when I do need to scale up, I have a system I will understand and will…

It sounds like the main benefit to Elixir is that message handling is built into the language. How does that compare to using a message queue service like zeromq?

As macintux, said they don't really compare. Messaging is everywhere in Erlang, in a way that nobody would do with a message queue. For example, you don't read or write to a tcp socket; you receive and send messages to a 'port'. The same is true for file i/o. Rather than calling a method on a shared object, you generally would send a message to a process that owns the state (or a process that manages the state in a database).

Sending messages to processes on other nodes has the same syntax as sending to a process on your node, which makes it easy to run a distributed system. (Ports are different, you'd have to setup a proxy process on the remote node in order to send/receive from that).

Of course, with the base of process to process messaging you can build a higher level messaging queue (see RabbitMQ for a popular message queue built in erlang).

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