Dave,
That's a great question and I look forward to the answer. I'll add this to your question: for those of us not using journaling file systems, what is it that "most commercial databases do"? Does a standard installation of Oracle (that is not using an Oracle file system or appliance) operate in fsync mode, no fsync mode, or something in between? Is there a period of time in which a power failure or OS crash would cause data loss?