[viraptor]

You cut a lot from reason 2. The was an important part. I've seen a system where the backups were made. They were verified too. Only after an actual data loss it was discovered that the backup verification was faulty and half of the "verified" and "properly backed up" data was missing.

My point is that you can spend lots of hours trying to backup your data and verify its correctness. But unless you put it back into the actual working environment and check every single bit of it, you cannot be sure it was a proper backup - not with 1GB of information and certainly not with 1TB. And then after you verified that you can verify that you have backups, something will fail and a bunch of people will say "if you didn't check the backups properly, it's your fault". I've seen backup systems fail in amazing ways and will probably never again believe that you can be "sure".