Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

How Discord Scaled Elixir to 5M Concurrent Users

blog.discordapp.com

Post reply on HN
Print view View original

31–40 of 260 posts

Re: How Discord Scaled Elixir to 5M Concurrent Users

#31

Post by Vishnevskiy »

joonoro wrote: post #14

Elixir was one of the reasons I started using Discord in the first place. I figured if they were smart enough to use Elixir for a program like this then they would probably have a bright future ahead of them. In practice, Discord hasn't been completely reliable for my group. Lately messages have been dropping out or being sent multiple times. Voice gets messed up (robot voice) at least a couple times per week and we…

The messages struggles have been sadly due to issues with Cassandra and GC pauses caused by bugs within it. We have been trying to work with the Cassandra developers to resolve these.

Voice issues should not be happening. Please contact our support with more information and we will gladly investigate.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#32

Post by cschneid »

jaequery wrote: post #18

Anyone know if Phoenix/Elixir have something similar to Ruby's bettererror gem? I see Phoenix has a built-in error stack trace page which looks like a clone of bettererror but it doesn't have the real-time console inside of it. Also, I wish they had a ORM like Sequel. These two are really what is holding me back from going full in on Elixir. Anyone can care to comment on this?

> like Sequel

Ecto can do a reasonable impression with its DSL & direct use of tables. You don't need to go through the whole stack of schemas and such.

What in particular do you like about Sequel (over what Ecto is providing)?

Re: How Discord Scaled Elixir to 5M Concurrent Users

#33

Post by lojack »

cutler wrote: post #11
myth_drannon wrote: post #6

It's interesting how on StackOverflow Jobs Elixir knowledge is required more often than Erlang. http://www.reallyhyped.com/?keywords=erlang%2Celixir

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.

Following this logic it'd only ever be possible for mainstream technologies to ever achieve mainstream adoption.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#34

Post by kornish »

mbesto wrote: post #7

This is one of those few instances where getting the technology choice right actually has an impact on cost of operations, service reliability, and overall experience of a product. For like 80% of all the other cases, it doesn't matter what you use as long as your devs are comfortable with it.

Not sure why this comment saw a couple downvotes earlier. mbesto is correct: for most startups, most of the time, competitive advantage doesn't come from the underlying tech stack. To make a general statement, most things could be done similarly on any of several platforms. However, when product requirements match exceptionally well with a specialized technology, you can see things that would simply be infeasible or extremely tough using a different stack.

WhatsApp + Erlang was one of those cases (watch this talk and imagine trying to recreate that system with only a handful of server engineers using any other tech: https://www.youtube.com/watch?v=c12cYAUTXXs). Discord + Elixir appears to be another.

Curious if anyone has any examples that spring to mind from outside the highly concurrent messaging space.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#35

Post by ConanRus »

I do not see there any Elixir specific, it is all basically Erlang/Erlang VM/OTP stuff. When you using Erlang, you think in terms of actors/processes and message passing, and this is (IMHO) a natural way of thinking about distributed systems. So this article is a perfect example how simple solutions can solve scalability issues if you're using right platform for that.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#36

Post by mahyarm »

jakebasile wrote: post #16

I'm continually impressed with Discord and their technical blogs contribute to my respect for them. I use it in both my personal life (I run a small server for online friends, plus large game centric servers) and my professional life (instead of Slack). It's a delight to use, the voice chat is extremely high quality, text chat is fast and searchable, and notifications actually work. Discord has become the de facto pl…

They could side step to corporate slack on-prem chat style solutions and be a pretty strong contender. They were scaling huge chat rooms and such way better than slack was a year ago.

But they seem to refuse suggestions to do so continuously, so they seem to have some business plan somewhere.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#37

Post by toolz »

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…

I think the next big push in elixir is tooling around metrics. Once there are hard numbers to market to non-techies I think we'll see a large shift towards elixir.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#38

Post by bsder »

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…

> I see a bright future for Elixir, and a breath of fresh air for Erlang.

Is Erlang really that much of a barrier? Erlang was a touch odd, but I didn't find the language itself that mind-bending. Wrapping my head around the proper way to structure things and the proper use of the OTP libraries was much more time-consuming. That level of architectural thought doesn't magically go away because you changed the language.

About the only thing I found irritating was a lack of language support for mutable hash tables, but I thought they fixed that at some point.

And Erlang's bit packing/unpacking borders on magical in terms of expressiveness and speed. I wish other languages would adopt it.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#39

Post by jakebasile »

lordCarbonFiber wrote: post #25
jakebasile wrote: post #16

I'm continually impressed with Discord and their technical blogs contribute to my respect for them. I use it in both my personal life (I run a small server for online friends, plus large game centric servers) and my professional life (instead of Slack). It's a delight to use, the voice chat is extremely high quality, text chat is fast and searchable, and notifications actually work. Discord has become the de facto pl…

A closed source walled garden chat service that survives purely on the free flow of VC capital 100% has no long term viability. No federation means as soon as the "next thing" shows up and wins way the VC dollars they'll disappear. It's so incredibly frusterating that so many companies and users make/support these closed environments even as we enter a new golden age of open sourced and federated technologies.

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.

Re: How Discord Scaled Elixir to 5M Concurrent Users

#40

Post by mononcqc »

cschneid wrote: post #29
rdtsc wrote: post #5

Good stuff. Erlang VM FTW! > mochiglobal, a module that exploits a feature of the VM: if Erlang sees a function that always returns the same constant data, it puts that data into a read-only shared heap that processes can access without copying the data There is a nice new OTP 20.0 optimization - now the value doesn't get copied even on message sends on the local node. Jesper L. Andersen (jlouis) talked about it in h…

Are there good resources / books on advanced BEAM? I'd love to know more of the nitty-gritty details of the VM, and how to make the best use of it.

https://github.com/happi/theBeamBook for the VM

http://erlang-in-anger.com/ for introspecting it in production

Post reply on HN