By Bhavin Turakhia CEO, Directi. Covers: * Why scalability is important. Viral marketing can result in instant success. With RSS/Ajax/SOA number of requests grow exponentially with user base. Goal is to build a web 2.0 app that can server millions of users with zero downtime. * Introduction to the variables. Scalability, performance, responsiveness, availability, downtime impact, cost, maintenance effort. * Introduction to the factors. Platform selection, hardware, application design, database architecture, deployment architecture, storage architecture, abuse prevention, monitoring mechanisms, etc. * Building our own scalable architecture in incremental steps: vertical scaling, vertical partitioning, horizontal scaling, horizontal partitioning, etc. First buy bigger. Then deploy each service on a separate node. Then increase the number of nudes and load balance. Deal with session management. Remove single points of failure. Use a shared nothing cluster. Choice of master-slave multi-master setup. Replication can be synchronous or asynchronous. * Platform selection considerations. Use a global redirector for serving multiple datacenters. Add object, session API, and page cache. Add reverse proxy. Think about CDNs, Grid computing. * Tips. Use a Horizontal DB architecture from the beginning. Loosely couple all modules. Use a REST interface for easier caching. Perform application sizing ongoingly to ensure optimal hardware utilization.