Service level indicator

In information technology, a Service Level Indicator (SLI) is a measure of the service level provided by a service provider to a customer. SLIs form the basis of Service Level Objectives (SLOs), which in turn form the basis of Service Level Agreements (SLAs); an SLI is thus also called an SLA metric.

Common SLIs include latency, throughput, availability, and error rate; others include durability (in storage systems), end-to-end latency (for complex data processing systems, especially pipelines), and correctness.