What are some key things to remember when scaling a large system? — 1) Asynchronous is good (use queues, topics/pub-sub) 2) Parallel is good (multi-threading, load balancing etc.) 3) Avoid points of contention e.g. synchronization 4) Avoid writing to disk until you must - cache like crazy 5) Scale out not up 6) At web scale the speed of light is a problem 7) At web scale everything fails - networks, load balancers etc.