This document summarizes notes from several talks and discussions about scaling Ruby on Rails applications. Some key points include: - To scale a Rails app, focus on load balancing and separating application tiers (front-end servers, application servers, databases). Use caching, database replication, and queuing systems. - Monitoring tools like Munin and Nagios are important for tracking performance bottlenecks. Metrics like requests per second help determine capacity. - Scaling the database is critical; techniques include sharding, replication, and optimizing queries with indexing. Caching data in Memcached also helps scale performance. - Virtualization allows consolidating servers. Software load balancers like Nginx can route