[linux-lvm] fsync() and LVM

[Ben Chobot]

On Fri, 13 Mar 2009, Stuart D. Gathman wrote:

> I suspect that LVM simply fails to pass the *write barrier* through
> to underlying layers (i.e. ignores the writebarrier call).  Thus, you should be
> fine if you simply turn off writeback caching in your disk drives.  If you
> could guarrantee that disk drives would be powered long enough after the main
> system stops - even a drive write back cache would not be much of a risk.

The big question in my mind is which software layers don't get to see the 
write barrier. If any of them can reorder writes, that could (however 
unlikely) lead to data corruption.