“With over 15 billion page views a month Tumblr has become an insanely popular blogging platform. Users may like Tumblr for its simplicity, its beauty, its strong focus on user experience, or its friendly and engaged community, but like it they do.
Growing at over 30% a month has not been without challenges. Some reliability problems among them. It helps to realize that Tumblr operates at surprisingly huge scales: 500 million page views a day, a peak rate of ~40k requests per second, ~3TB of new data to store a day, all running on 1000+ servers…”