[jrallison]

async != an incorrect system. Cash machines are a good example of an asynchronous, eventually consistent system that works. As is any well built eventually consistent data store.

Redis/Mysql has it's problems, as does all databases. However, as a practitioner it's important I know the shortcomings of each, so that I can know exactly what a certain database is offering in terms of safety and whether it's a good fit for my use-case. Antirez being open about them is a huge +1 in my book.

Data drift or loss of acknowledged writes isn't correct for a wide range of use-cases. If you know the limits, you can choose the incorrect system, and deal with the fallout when that "rare" event does happen.

[seiji]

async != an incorrect system.

Very correct! Most of the mysql problems derive from it being statement replication and not log shipping. A proper postgres replication setup will be less prone to having data inconstancies.