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Reliability Metrics

Uptime

Uptime is the time a service was available during a period.

What is uptime?

Uptime describes the time a service was available during a period. In reliability work, the label is useful only when it maps to a measurable check, a clear owner, and a next action when expectations break. Without that operational meaning, the phrase becomes decoration in dashboards and status updates.

Why it matters

Uptime matters because teams need a precise shared meaning for the time a service was available during a period. Vague language turns incidents into arguments about words instead of fixes.

When everyone uses the same definition, alerts, status updates, and post-incident reviews stay aligned.

How it works

In practice, the time a service was available during a period shows up as a concrete signal you can measure or communicate. Operators define what good looks like, watch for deviations, and record what happened when expectations break.

The useful version of uptime is operational: it changes who gets notified, what customers see, or which metric a team reviews after an incident.

Practical example

Imagine a team operating around api.example.com available for 29 days 23 hours in a month. When observed behavior stops matching the definition of uptime, the team treats that change as a reliability event with a clear owner and next step.

Common misconception

Uptime is a vendor marketing badge with one universal formula

That reading usually collapses distinct ideas into one slogan. Keep uptime tied to observable behavior so the definition stays useful under pressure.

How Fajita handles this

Fajita derives uptime views from monitor history and status-page history. Definitions of eligible time can vary.

Related documentation

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