On Thu, Nov 29, 2001 at 05:51:45AM -0500, Brian A. Seklecki wrote:
> >   So, am I misunderstanding what synchronous mode means?
> >
> 
> Perhaps you're confusing journaling file system supprt on Solaris UFS and
> Linux XFS or EXTFS3 or Veritas FXFS with a "transaction log" that you can
> 'roll' w/ simple BSD FFS 'softdeps'

  No, I don't think I am thinking of journaling or LFS or anything.  The
mount man page says that under the sync option:
 
     All I/O to the file system should be done syn-
     chronously. This is not equivalent to the normal mode
     in which only metadata is written synchronously.

  What does "synchronously" mean?  I thought it meant that if you are
writing two different blocks to the disk, you'll launch the write
for one, wait until it completes, and then launch the write for the
other.

  I thought, that if you mount with sync, _all_ disk operations (data
and metadata) should be completely serialized, and therefore if you
power-off abruptly, there should only be at most one metadata transaction
in progress.  There might be several transactions that are completely
lost, but that's fine -- at least the disk is consistent.
  
  From experience, this (all disk operations are serialized) is not what
synchronous means.  :(  So I need enlightenment!

  Brian