[Re: Unclean sync in current

Kevin Oberman wrote:
> 
> I've been seeing this for a couple of weeks since I updated my laptop to
> CURRENT. I do a normal shutdown (-p or -r) and reboot. The shutdown
> looked normal, with no problems reported with the sync, but, when the
> system is rebooted, the partitions are all shown as possibly
> unclean. From my dmesg:
> Mounting root from ufs:/dev/ad0s3a
> WARNING: / was not properly dismounted

[ ... ]

There was an issue reported some time back about the power being
shut off before the disks had been forced to sync their write
caches out to stable storage, resulting in this behaviour.

I believe Soeren updated the driver to force this sync before
returning, at least for ATA drives, so you may just be running
stale code.  Alternately, you may just have disk drives that
ignore the command.

I think it was controlled by a sysctl with "sync" in the name,
so you might want to look it up via:

	sysctl -A | grep sync

if you are in fact running the most recent -CURRENT.  I think
there was a delay factor, in seconds, involved (FWIW).

Another alternative is to disable write caching on the disk,
as a workaround (amazing how many times recently that that's
been the answer to someone's problem...).

-- Terry