转：190亿美元的whatsapp架构

原文：

http://highscalability.com/blog/2014/2/26/the-whatsapp-architecture-facebook-bought-for-19-billion.html 

Platform

Backend

• Erlang

• FreeBSD

• Yaws, lighttpd

• PHP

• Custom patches to BEAM (BEAM is like Java’s JVM, but for Erlang)

• Custom XMPP

• Hosting may be in Softlayer
  

Frontend

• Seven client platforms: iPhone, Android, Blackberry, Nokia Symbian S60, Nokia S40, Windows Phone, ?

• SQLite

Hardware

• Standard user facing server:

• Dual Westmere Hex-core (24 logical CPUs);

• 100GB RAM, SSD;

• Dual NIC (public user-facing network, private back-end/distribution);

Product

• Focus is on messaging. Connecting people all over the world, regardless of where they are in the world, without having to pay a lot of money. Founder Jan Koum remembers how difficult it was in 1992 to connect to family all over the world.

• Privacy. Shaped by Jan Koum’s experiences growing up in the Ukraine, where nothing was private. Messages are not stored on servers; chat history is not stored; goal is to know as little about users as possible; your name and your gender are not known; chat history is only on your phone.