Here are the slides from my talk at DotScale 2016 conference. Erlang is a programming language dedicated to building robust and scalable services. It has matured for many years and finally reached a point where it is one of the secret weapon used by many prominent companies. To help you understand Erlang, I am going to walk you through old programming concepts that are at the root of Erlang using … A time machine !

1. Building Scalable Systems
What you can Learn from Erlang

3. First Stop: 1973

4. Actor Model
• Carl Hewitt

5. Actor Model Principle
• An actor can:
• Send Messages to other Actors
• Create other Actors
• Process Next Message

6. Share Nothing

7. “An Island of Sanity in a Sea of Concurrency"
Actor
State
Actor
State
Actor
State
Actor
State
Actor
State

8. Naturally scalable

9. Next stop: 1986

10. Birth of Erlang
Joe Armstrong, Robert Virding, Mike Williams, Bjarne Däcker

11. Share Nothing with Lightweight
Processes

12. Let it Crash

13. Handle Failures with Process Links
and Supervisors

15. Next stop: 1998

16. Erlang VM released as Open
Source

17. Erlang strength lies in the VM

18. Vertical scaling:
Multicore and Scheduler

19. Horizontal scaling:
Clustering
Transparent, well almost

20. Erlang strengths match
Server applications properties
• Server apps are most of the time IO bound
• Server apps are often memory bound.

21. Network
Stack
Accepted connections
Requests processing
Server threads
Pool
Thread
Thread
Thread
Thread
Thread
Thread
Thread
Thread
Thread
…
Client
Requests
X
X
X
Connections Pool
i.e. Apache

22. Network
Stack
Accepted connections
Requests processing
Lightweight processes
Client
Requests
…
One Connection per
Thread
Erlang webservers
i.e. Yaws, Cowboy, etc.

23. Design comparison
• Number of requests handled in
peak time: 1Ks to 10ks
• Throughput: reduce quickly
when max concurrency
reached
• More complex code
• Number of concurrent requests
handle in peak time: 100Ks to
1Ms
• Throughput: Higher for large
number of concurrent requests.
• Simple code, no pool to
manage
Design with worker thread pools Design with Erlang processes

24. Back to 2016

25. Erlang is still the Reference for
Scalable Systems

26. Makes it easier to build
Advanced Concurrency Patterns

27. New languages using the
Erlang VM: Elixir, LFE, etc

28. Inspiration for new languages /
Frameworks:
Go, Scala, Akka, Clojure, …

29. Next Stop ?