pktcdvd and backups

Some time ago an HDD I had quite a while died. The worst part is, that it contained the backups. It worked for about two years in a fashion where it gets powered once in a while via a mosfet, receives a payload of backups and then goes offline again. Analyzing the corpse it looks like it was the spindel motor. Well done, WD!
This made me thing of another way to store critical backups. Consider me paranoid, but I do not trust cloud services.  Then I saw an old cdrw disk wasting its remaining life as a stand for the coffee cup.