2. WD 1TB, 2TB and 3TB Green drives. Various subversions of them
Hm. I had two WD 2TB drives fail in quick succession in my Synology NAS recently. I wonder if there's something to this.
I am afraid Drobo dashboard does not report drive temp.
Feel 'em with your finger. Are they like OMFG hot, or just nicely warm?
4. Not sure HOW they fail. RED led next to the failed drive. I've just been replacing the drives without further investigation.
Might be worth connecting the failed drives into a PC and using a S.M.A.R.T utility to read stats. Maybe there's nothing physically wrong with the drives and the Drobo firmware has some kind of a partition-mangling bug.