I have 28 of those discs. 18 are dead, one is destroyed by my parter and 9 are still in production.
One is dying right now:
Device: /dev/da17 [SAT], Self-Test Log error count increased from 0 to 1
Device: /dev/da17 [SAT], 8 Offline uncorrectable sectors
Device: /dev/da17 [SAT], 8 Currently unreadable (pending) sectors
So that's my disks. Freaking Seagate. When I emailed them, they just answered that "Desktop Class Discs cannot be powered 24/7 and must be powercycled" -- Because we don't know physics.
Well that's my story. :(