Re: no universally correct setting for fsync

Robert Haas <robertmhaas@gmail.com> wrote:
 
> "It might be safe" is a bit of a waffle.  It would be nice if we
> could provide some more clear guidance as to whether it is or is
> not, or how someone could go about testing their hardware to find
> out.
 
I think that the issue is that you could have corruption if some,
but not all, disk sectors from a page were written from OS cache to
controller cache when a failure occurred.  The window would be small
for a RAM-to-RAM write, but it wouldn't be entirely *safe* unless
there's some OS/driver environment where you could count on all the
sectors making it or none of them making it for every single page. 
Does such an environment exist?
 
-Kevin