Systems
Uptime
Plain English
How often something is working.
Definition
Uptime is the proportion of time a glossarySystemA system is a collection of interconnected components that work together to achieve a specific function or outcome.Open glossary term is operational and reachable, usually expressed as a percentage. It measures availability rather than correctness, so a system can post high uptime while behaving badly.
In practice
Often expressed as a percentage, such as 99.9% uptime.
In context
It is quoted in nines and experienced in minutes. Ninety-nine point nine per cent still allows the better part of nine hours offline a year.
The reality
High uptime does not always mean a good serviceUser ExperienceImprove journeys, reduce friction, and make digital products clearer, simpler, and easier to move through.Open service if glossaryPerformancePerformance refers to how quickly and efficiently a system responds to user actions and processes tasks.Open glossary term is poor.
Compared with
Uptime vs Reliability
Uptime measures whether the glossarySystemA system is a collection of interconnected components that work together to achieve a specific function or outcome.Open glossary term was reachable. glossaryReliabilityReliability is the ability of a system to consistently perform as expected without failure.Open glossary term covers whether it behaved correctly. Uptime is the easier number to report, which is why it gets reported.
FAQ
Common questions
A few practical answers to the questions that usually come up around this term.
What is uptime?
It is how long a glossarySystemA system is a collection of interconnected components that work together to achieve a specific function or outcome.Open glossary term is available.
Why is uptime important?
It reflects glossarySystemA system is a collection of interconnected components that work together to achieve a specific function or outcome.Open glossary term glossaryReliabilityReliability is the ability of a system to consistently perform as expected without failure.Open glossary term.
What is good uptime?
Typically 99.9% or higher.
What is the downside of focusing only on uptime?
glossaryPerformancePerformance refers to how quickly and efficiently a system responds to user actions and processes tasks.Open glossary term and quality may still suffer.
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