Short of inherent big data problems, such as crawling the entire web, you won't need database scaling until you're already not a startup any more. Cassandra an

Short of inherent big data problems, such as crawling the entire web, you won't need database scaling until you're already not a startup any more. Cassandra and similar technologies constrain your queries and make schema changes incredibly expensive. This is the opposite of what you need in a startup. You need flexibility.