Your website FAQ question 1 says it's standard MySQL. In another comment here you say: "a new database which we've built ourselves, which we've announced but i

Your website FAQ question 1 says it's standard MySQL. In another comment here you say: "a new database which we've built ourselves, which we've announced but isn't publicly available yet." If it's standard MySQL, then you hit the same issues as if I were to host MySQL myself. If it's your own database you've built yourself, but is not available yet, then I am not going to trust it with my data. In what I do I often need to have a high-availabilty website where by a loss of connectivity, flood, power issue etc in that data centre can cause outages. Most of the time on our critical projects we have one or two physical data-centers with EC2 for testing and disaster recovery. Although being based in Europe - we do a lot of work in SE Asia. The connectivity between Asia and Europe (often you end up with 400ms+ RTT and 10% packet loss) means you have to host local websites in the region, and even in country (you might be able to drive between Malaysia and Singapore, but the internet inter-connectivity is terrible). If you have any kind of application that ever needs high levels of read-write traffic you quickly end up needing to distribute the database in some way, and for this type of application, it's an awful lot easier to build upon Cassandra and do a bit more work in the application then to try and get MySQL or PostgreSQL to act as a multi-site, multi-master database over sub-optimal links.