With O_DIRECT you won't hit that bug. MySQL/InnoDB allows you to do that (not the default). However I think you're not very likely to hit this bug. This is why you have backups and replication.
I agree, this is in some ways a storm in a teacup and unlikely to cause silent data loss (it requires transient failure, but in reality failure storage probably fails completely and you definitely know about that). But as a matter of principle, it's bad that an operating system is so callous with my data.
On the plus side, I think this is great PR for FreeBSD (any filesystem) and ZFS (any OS).
One thing I'm curious about... MySQL still calls fsync() when you use O_DIRECT. See the warnings in the documentation about why O_DIRECT_NO_FSYNC is dangerous (to avoid loss of eg XFS meta-data, otherwise it might forget that a file was truncated or extended). I wonder if in some vanishingly rare failure mode you could lose data that way even with O_DIRECT.
