For what it's worth, this is pretty much exactly what we did at the last web property I ran with ~500 million monthly pageviews. We had a configuration framewo

For what it's worth, this is pretty much exactly what we did at the last web property I ran with ~500 million monthly pageviews. We had a configuration framework that allowed us to flip bits on the fly (and, importantly, flip them back), without a deploy, in ~1 second across all of our app servers. The app servers listened to a message queue which would broadcast changes of configuration values. This one thing alone made a huge difference in our engineering velocity. If you're looking for a pre-built component to do these things for you today, check out Apache Zookeeper: http://hadoop.apache.org/zookeeper/ http://hadoop.apache.org/zookeeper/