Requirement
Pattern
Availability
Description This pattern expresses the minimal percentage of time in which the system shall be operative.
Comments ----
Pattern goal Aim at having the system operative a reasonable percentage of time.
Author GESSI-SSI
Sources (0..*)
  • Requirement books from SSI
  • Specialized literature
Keywords (0..*)non-stop, running time
Dependencies (0..*)IMPLIES Downtime
IMPLIES Uptime
Requirement
Form
Availability
Description This form expresses the need of ensuring some availability level given as a percentage
Comments In the literature availability it is usually defined as the ratio of the Uptime / (Uptime + Downtime).
Version date 2009-03-20 00:00:00.0
Author GESSI-SSI
Sources (0..*)
  • Requirement books from SSI
  • Specialized literature
Fixed PartQuestion text ----
Form text The system shall have a minimal availability rate of %availabilityLevel%%
ParameterMetric
availabilityLevel: is the rate of time that the system must provide servicePercentage: Percentage = Real