Yes, wouldn't their fix likely make etcd not consistent anymore since there's no guarantee that the data was persisted on disk?
And also in prod, etcd recommends you run with SSDs to minimize variance of fsync/write latencies
Edit: I meant what sequence of events would cause etcd to go into an inconsistent state when fsync is working this way
The purpose of the demo wasn't to show consistency, but to describe the policy-driven decision/mechanism.
What hit us in the first place (and I think this is what we should fix) is the fact that a brand new nuc-like machine, with a relatively new software stack for spawning VMs (incus / ZFS etc.) behaves so bad it can produce such hiccups for disk IO access...