For a Reserved Instance (RI) in AWS environments, nfu is a measure of RI capacity that you can use to compare or combine that capacity for different template families. For AWS environments, Turbonomic measures RI utilization and coverage in terms of nfu.
Measuring by nfu gives a common measure for RI capacity across different instance families. For example, assume ts_small factors to 1 nfu, while ts_large factors to 4 nfu. If you reserve one small and one large workload, your RI consumption is 5 nfu.