Most products labelled as "database" afford most if not all of the ACID guarantees. Redis offers none by default. It's a database in the loosest sense of the wo

Most products labelled as "database" afford most if not all of the ACID guarantees. Redis offers none by default. It's a database in the loosest sense of the word, so it's a database alright, but then so is a text file. The problem is that in practice, some people will assume that it, being a "database", has similar properties to the other databases they know when it doesn't. I've had heated debates in meetings, and I wasn't just spewing an opinion but pointing at the documentation. In the latest case, that involved replication in a cluster, there is absolutely no guarantee (or there wasn't at the time that happened) of consistency between members. The developers had assumed there was. It's the kind of assumption that works just fine and dandy in a staging environment, but breaks subtly and painfully in production, eventually.