alt Hacker NewsI think “most people will have to turn on the setting to make things fast at the expense of durability” is a dubious assertion (plenty of system, even high-criticality ones, do not have a very high data rate and thus would not necessarily suffer unduly from e.g. fsync-every-write).
Even if most users do turn out to want “fast_and_dangerous = true”, that’s not a particularly onerous burden to place on users: flip one setting, and hopefully learn from the setting name or the documentation consulted when learning about it that it poses operational risk.
I always think about the way you discover the problem. I used to say the same about RNG: if you need fast PRNG and you pick CSPRNG, you’ll find out when you profile your application because it isn’t fast enough. In the reverse case, you’ll find out when someone successfully guesses your private key.
If you need performance and you pick data integrity, you find out when your latency gets too high. In the reverse case, you find out when a customer asks where all their data went.