http://blog.twitter.com/2013/new-tweets-per-second-record-and-how

Raffi Krikorian, Twitter’s Vice President of Platform Engineering, shared in a blog post Friday how the company went from essentially a patchwork infrastructure to one that could handle almost 143,000 tweets per second, a new record set last week. Twitter did this by blending its homegrown and open source technologies. What a marvelous read for the weekend.