Requirement
Pattern
Downtime
Description This pattern expresses the maximum unavailability periods required for the system
Comments ----
Pattern goal Fix the maximum unavailability periods of the system
Author GESSI-SSI
Sources (0..*)
  • Requirement books from SSI
  • Specialized literature
Keywords (0..*)security, stop time, time to repair
Dependencies (0..*)IMPLIES Availability
IMPLIES Uptime
Requirement
Form
Downtime
Description This form expresses the maximum allowed unavailability period of the system
Comments Be aware that a zero downtime is almost not possible except for highly critical systems. The lower the downtime, the more expensive the system is.
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 unavailability periods shorter than %amountOfTime% %timeUnit1% per %timeUnit2%
ParameterMetric
timeUnit2: is the second unit of time corresponding to a time interval; it must be broader than timeUnit1TimeUnitType: TimeUnitType = Domain(Days, Hours, Minutes, Seconds, Miliseconds, ...)
timeUnit1: is the first unit of time corresponding to a time intervalTimeUnitType: TimeUnitType = Domain(Days, Hours, Minutes, Seconds, Miliseconds, ...)
amountOfTime: is a number that indicates time durationamountOfTimeUnitType :
Extended Part Timed DowntimeQuestion text ----
Form text The system shall particularly not be unavailable from %startingTime% to %finalTime%
ParameterMetric
startingTime: are time points that defined the period over which the restriction applies; it must hold that startingTime < finalTimeUptimeInstant: UptimeInstant = TimePoint
finalTime: are time points that defined the period over which the restriction applies; it must hold that startingTime < finalTimeUptimeInstant: UptimeInstant = TimePoint