It can be done correctly
It can be done correctly. Paychex has six copies of its data center spinning in geographically distinct locations. Each has UPS and diesel generators. We had a utility power failure that lasted a good part of a week. I asked the Paychex representative how well their systems worked during this total loss of utility power. He said that everything worked perfectly. What did not work was their customers who had no adequate power plans. So Paychex had to rent trucks to visit their customers and hand-carry the data required to generate pay checks and deliver the completed pay checks back to their customers.
They could have lost five of their data centers and still been in business. This is a company that understands where their crown jewels are and protects them correctly. They don't trust clouds or third-party suppliers for this (or at least didn't a few years ago).
Biting the hand that feeds IT
