Our expectations are every day higher and more demanding. This is also reflected in our personal and business software applications. How long has Instagram been down this year? When was the last time your CRM system was not available? Have you had any payment delayed recently?
How much or how long are you willing to tolerate?
This is actually known a SLA, Service-Level Agreement, which defines the performance standards that a company or service commits to for you as a customer or consumer of that service.
Performance commitments are commonly measured as a percentage. That percentage typically ranges from 99.9 percent (“three nines“) to 99.99 percent (“four nines“).
How do percentages relate to total downtime?
Downtime refers to the time duration that the service is unavailable.
The following table summarises the relationship between the percetage and the corresponding downtime.