>> More later ... I installed OpenBSD 5.0 on the same machine, similar setup (all filesystems noatime except /tmp and /home, which are both async,noatime). I repeated my experiment -- wrote a new file in my home directory, waited a few minutes, and killed the power. On reboot, there were complaints from the fscks, async and not, all fixed. The system came up without a manual fsck and the new file was present in my directory. So meta-data for async filesystems is being written within a window of a handful of minutes with OpenBSD.
/Don
