Disaster recovery for small and medium business risky and costly exercise. Either you don’t have it because it is too expensive or it is not regularly tested. We have just commissioned a Natural Gas generated alternative power source to run our critical hardware in the event of power failure. This has been implemented at a much lower cost than expected and gives us up to 10.4 kva on natural gas. Plenty of output for small/medium business requirements.

Increasing UPS (battery) reserves to cover a lengthy power outage is expensive.  An alternative is to implement a generator and enough battery reserve to cover the automated start of the generator.  In this way you have the best of both, zero downtime (the UPS covers the 10 second changeover) and the generator supplies power until mains supply is back and consistent (which can be many hours).