7.6 When Not to Use Redis

A system of record is the store whose copy of the data counts when copies disagree, and the one you restore from after a loss. Most misuse of Redis comes from letting it become a system of record without deciding to. Because Redis is fast, flexible, and already in most stacks, a cache gradually becomes a session store, then a queue, and then the only database for one feature. Eventually an outage shows that nobody planned for Redis to hold the only copy of something important.

This lesson follows one online store through that decision