Symptoms
Availability Formulas which calculate device availability based on sysUpTime (name='Uptime') such as availability.Availability, availability.AllInOne etc, only show data for a maximum of 1 month even if longer time periods and higher aggregations are selected:
Cause
This is expected behaviour. As per the documentation, these formulas can only use real-time data:
Availabilityavailability.Availability
This formula computes the availability from the sysUpTime metric.
This formula expects sysUpTime as parameter, and will return 100 when the device is up and 0 when it is down.
A major drawback of such a calculation is that real-time values need to be used.As a consequence, it cannot use pre-defined aggregates and may retrieve a lot of data.
This formula uses the availability.SystemDowntimeDuration formula, which means it has to be present too.
Parameters
sysUpTime - The sysUpTime metric.
Results
Availability (%) - This formula returns the device availability.
By default the apg timeseries database only holds 1 month of real-time data. This is why only 1 month of data is seen in graphs that result from these formulas.
Resolution
To report device availability statistics older than 1 month, the Availability metric should (name='Availability') as this metric is calculated at the collecting level based on the delta between two uptime metrics.
