From: "Frank Haber" 

Y'know, I don't think I've ever seen a review of motherboard or PCI-card
hardware mirroring from a reliability and recovery standpoint. The reviews
tend to be RAID0/gamer oriented. Do the utils work?  Who knows?  Can you,
at least temporarily, mirror to a slighly different drive for recovery, if
the failed HD is long out of production and you can't buy a dupe? Is there
any time advantage in pre-striping a spare?  What about HDs on the shelf? 
Keeping a HD without spinning it up every six months used to be a no-no
(stiction). Have lubes improved that much, or are you going to have to keep
a 5-12V bench supply in the closet and mark the calendar to spin up all
your spares every New Year's and Fourth of July?

OTOH, the horror stories I heard about certain (parallel-)ATA RAID0 setups
early on seem to have settled down.

After Geo. jogged my memory about the RAID1 speed penalty on writes, I've
been keeping an eye out for comparisons on that (HW vs. SW, brands of
controllers, gotchas on certain levels of drive firmware, pathological
cases of split cache writing/MFT expansion, etc.)  I've seen *nothing*. 
This is strange.  I don't know why I've never used mirroring.  It's not as
though those monster, cheap HDs don't ever fail.

--- BBBS/NT v4.01 Flag-5