This document a) defines metrics as key performance indicators (KPIs) for resilience, dependability, fault tolerance and availability tolerance for data centres; b) covers the data centre infrastructure (DCI) of power distribution and supply, and environmental control; c) can be referred to for covering further infrastructures, e.g. telecommunications cabling; d) defines the measurement and calculation of the metrics and resilience levels (RLs); e) targets maintainability, recoverability and vulnerability; f) provides examples for calculating these KPIs for the purpose of analytical comparison of different DCIs. This document does not apply to IT equipment, cloud services, software or business applications.