Having stored money values in Redis several times in the past (sometimes without replicas at all!), the answer is knowing how much you can trust the system. I

Having stored money values in Redis several times in the past (sometimes without replicas at all!), the answer is knowing how much you can trust the system. I trust enough to get the job done, but not enough to get bitten when these systems drop data. Because here's the truth: they all drop data.