fsync(2) manual and hdd write caching

[Alexander Best]

On Wed Oct 27 10, Bruce Cran wrote:
> On Tue, 26 Oct 2010 21:36:18 +0000
> Alexander Best <arundel at freebsd.org> wrote:
> 
> > since there's a thread on freebsd-questions@ concerning fsync(2) and
> > the fact that hdd write caching can cause this syscall to basically
> > be a no op, could somebody please copy the BUGS section from sync(2)
> > to fsync(2)?
> 
> Shouldn't the BUGS section of sync(2) be removed?
> 
> "The sync() system call may return before the buffers are completely
>      flushed."
> 
> But from
> http://www.opengroup.org/onlinepubs/009695399/functions/sync.html : 
> 
> "The writing, although scheduled, is not necessarily complete upon
> return from sync()."
> 
> That would suggest it's not actually a bug.

well...you are right on the one hand. but still this should be documented imo.
how about turning BUGS into a CAVEATS section and then adding that section to
fsync(2)?

the reason posix mentions this sync/fsync behavior is probably the fact that
they know that this cannot be avoided. so that statement seems itself to be a
caveat rather than a feature. ;)

cheers.
alex

> 
> -- 
> Bruce Cran

-- 
a13x