Browse Definitions:

uptime and downtime

This definition is part of our Essential Guide: Server uptime and hardware failure guide

Uptime is a computer industry term for the time during which a computer is operational. Downtime is the time when it isn't operational. Uptime is sometimes measured in terms of a percentile. For example, one standard for uptime that is sometimes discussed is a goal called five 9s - that is, a computer that is operational 99.999 percent of the time.

This was last updated in September 2005

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It amazes me that, as familiar as we are with these terms, we never flip them around and consider the work itself. Look at a typical ticket in IT, and it will spent more time waiting to be picked up, or waiting for a decision, than processed - probably by a factor of 100X.

That is to say, from customer request to problem solved, a problem that might take an hour of work and two questions and answers could take 100 business hours - two and a half weeks - to solve. That's a downtime of 99%! Why don't we talk about that as much as we talk about computers?


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