Hello Michael,
MvE> Please check wether these drives have write caching
> enabled with something like: dkctl wd0 getcache.
# dkctl wd1 getcache
/dev/rwd1d: read cache enabled
/dev/rwd1d: read cache enable is not changeable
/dev/rwd1d: write cache enable is changeable
/dev/rwd1d: cache parameters are not savable
#
-Andy