Facebook is now running the daily configuration of its millions of servers with an improved configuration delivery process, replacing a more limited open source tool for distributing configuration data. Location Aware Delivery (LAD) is designed to keep configuration data from the distribution mechanism, have a latency time of less than five seconds, and support 10 times the file volume of the open source Zoo Keeper solution. LAD is comprised of a proxy that sits on every machine in the Facebook family and sends configuration files to any machine that wants or needs them. It also has a distributor to deliver configuration information by checking for updates, then generating a distribution tree for the set of machines needing an update. Among LAD’s achievements are boosting a 5MB update limit to 100MB, and raising a 2,500-user limit to 40,000 users.
More info here: TechCrunch, Ron Miller