Building large scale systems at Twitter

Very interesting article for building large systems at Twitter. Worth reading it, use of sharding on the top of standard mysql makes the trick (gizzard - for sharding , flockdb - for graph db) 

https://twitter.com/zipkinproject

http://www.youtube.com/watch?v=5cKTP36HVgI

http://highscalability.com/blog/2011/12/19/how-twitter-stores-250-million-tweets-a-day-using-mysql.html

http://highscalability.com/blog/2013/7/8/the-architecture-twitter-uses-to-deal-with-150m-active-users.html