Which sectors use them?

Any large volume of data that needs to be centralized, monitored and managed centrally needs a data center. Of course, a data center is not mandatory for all organizations that have embraced IT; it depends on the size and criticality of data. Data centers are extremely capital-intensive facilities. Commissioning costs run into millions of dollars, and operational costs involved in maintaining levels of redundant connectivity, hardware and human resources, can be stratospheric. The percentage of enterprises for which it makes business sense to commission and operate an enterprise data center is, consequently, extremely small.