The solution is that there are multiple solutions that are suitable in different situations. If you need "strict" requirements then it is likely impossible but

The solution is that there are multiple solutions that are suitable in different situations. If you need "strict" requirements then it is likely impossible but you can get close enough if you use sqlite. Or more lightweight atomic/thread-safe/fault-tolerant file library. You could rollout your own: it easy to start, and continue until the error rate is tolerable for your application (though it may take more dev time). If you don't need db-like strict guarantees. Just write your app knowing that it may fail (data may be lost, corrupted). It may be ok in a lot of cases.