There is no requirement to use the two components of DFS together; it is perfectly possible to use the logical namespace component without using DFS file replication, and it is perfectly possible to use file replication between servers without combining them into one namespace.
In 2016, the majority (51%) of the 8.4 million barrels per day (b/d) of crude oil produced in the Lower 48 states was light oil, or less dense oil with an API gravity of 40.1 or above. Light oil also made up more than half of the oil produced in 2015. API gravity is measured as the inverse of the density of a petroleum liquid relative to water. The higher the API gravity, the lower the density of the petroleum liquid, so light oils have high API gravities.
API is the only U.S. trade association that represents every aspect of America's oil and natural gas industry. For more than 75 years, API has led the development of petroleum and petrochemical equipment and operating standards. The API standards we can certify for include: API 6A.