Category
Reliability Metrics
Reliability metrics quantify how often a service works as expected and how quickly teams detect and recover from failure.
Why this category matters
Shared numbers let teams compare periods, set goals, and explain impact. Without clear definitions, uptime and MTTR become marketing language instead of operational tools.
Recommended learning order
- UptimeUptime is the time a service was available during a period.
- Uptime percentageUptime percentage is availability expressed as a percentage of eligible monitored time.
- AvailabilityAvailability is the share of time a service was able to fulfill its intended function.
- Mean time to detectMean time to detect is the average time from failure start to detection.
- Mean time to recoveryMean time to recovery is the average time from failure to restored service.
Foundational terms
- UptimeUptime is the time a service was available during a period.
- DowntimeDowntime is the time a service was unavailable during a period.
- AvailabilityAvailability is the share of time a service was able to fulfill its intended function.
- Uptime percentageUptime percentage is availability expressed as a percentage of eligible monitored time.
- Mean time to recoveryMean time to recovery is the average time from failure to restored service.
Advanced terms
- Mean time to detectMean time to detect is the average time from failure start to detection.
- Mean time between failuresMean time between failures is the average time from one failure to the next for a system.
- Service-level objectiveService-level objective is a target value or range for a service-level indicator.
- Service-level agreementService-level agreement is a contractual commitment about service level between parties.
- Service-level indicatorService-level indicator is a quantitative measure of some aspect of service level.