> I think Gordon's "spin down" idea is good, too... once the sync operation
> is complete, maybe spinning down the disk isn't such a bad idea, too...

Some power supplies need a minimum load to be happy.  Powering down
a disk could take its p/s below the minimum.

Perhaps a new "permission to power up/down via software" field in fstab?
Or a /etc/power_tab to allow a more general solution.

-Dave