Problems unmounting/fssyncking extern UFS filesystem

Kevin Oberman oberman at
Mon Nov 27 08:55:33 PST 2006

> Date: Mon, 27 Nov 2006 14:53:06 +0100 (CET)
> From: Oliver Fromme <olli at>
> Sender: owner-freebsd-stable at
> O. Hartmann wrote:
>  > Maybe amd() dismounts to early ... Don't know. Maybe the magic
>  > 'sync;sync;sync' before dismounting will help, I'll try it.
> As far as I know, that's not different from calling "sync"
> just once.  It might make more sense to put a little sleep
> between the sync calls, though.

The traditional mantra was
and not sync;sync;sync. The reason was timing. By entering the sync
command three times as fast as anyone could type, the sync could
reliably complete.

That mantra is about 25 years old, so its validity on modern hardware is
questionable, but the need for a delay is very real. I would suggest
something like: sync && sleep 5
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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