There are two kinds of people in the world - those who have had a data storage failure, and those who will.
Peter Krogh (an American photographer) designed the 3-2-1 principle :
- We recommend keeping 3 copies of any important file (a primary and two backups)
- We recommend having the files on 2 different media types (…), to protect against different types of hazards.
- 1 copy should be stored offsite (or at least offline).
I may add :
A. keep as many archive versions as you can (if a data corruption is discovered, one never know when it actually started to corrupt…)
B. if you’re an organization (several people managing the data), ensure that the owner of the offsite backup is different from the backup manager. (usually take the CEO, even if non tech)
Thus, any villain attitude (stopping backups or trying to corrupt everything) becomes complicated.
It’s always very arduous to help one who didn’t backup… And, dunno why, but without backups, I find it highly difficult to commiserate
( source in french )
BTW, to backup my OS, I usually use Back In Time (thus rsync) and not deja dup (duplicity).