What a terrible article...
If the data sets do not match then there is no redundancy.
The Unix command line has a wonderful tool called "diff," which compares files line by line.
Or, there's Git, which is even better.
What I'm getting at is that we are the first line of defense when it comes to our data.
I'm sure you've heard the colloquialism, "don't keep all your eggs in one basket?"
http://en.wikipedia.org/wiki/Data_redundancy
We have a term for what you're describing already - Backups