HOTSPOT How should you calculate the monthly uptime percentage? To answer, select the appropriate options in the answer area. NOTE: Each correct selection is worth one point.

To calculate the uptime percentage, you must determine the ratio of the actual operational time to the total scheduled time and then convert that ratio to a percentage.

1. Actual Operational Time (Numerator): This is calculated by taking the total possible time the service was scheduled to be available and subtracting any time it was unavailable.

• (Maximum Available Minutes – Downtime in Minutes)

1. Total Scheduled Time (Denominator): This is the total time frame being measured.

• Maximum Available Minutes

1. Percentage Conversion (Multiplier): To express the resulting ratio (a decimal) as a percentage, you must multiply it by 100.

• 100

The complete formula is: $\text{Availability \%} = \frac{(\text{Total Time} - \text{Downtime})}{\text{Total Time}} \times 100$

Microsoft. (2023). Service Level Agreements (SLA) for Online Services. Microsoft Licensing Documents.Reference: While specific calculation formulas are detailed in individual service SLAs, the concept is standardized. The SLA defines "Monthly Uptime Percentage," which is universally calculated by taking the total minutes in a month, subtracting the minutes of "Downtime," and dividing by the total minutes in the month.Lyu, M. R. (2007). "Software Reliability Engineering: A Roadmap." In Future of Software Engineering (FOSE '07). IEEE Computer Society, pp. 153–170.DOI: https://doi.org/10.1109/FOSE.2007.25Reference: This paper discusses software reliability and availability. On page 162, Availability ($A(t)$) is defined in its simplified form as a ratio of uptime to total time: $A(t) = \frac{\text{Uptime}}{\text{Uptime} + \text{Downtime}}$. This is mathematically equivalent to the formula in the answer: $\frac{(\text{Total Time} - \text{Downtime})}{\text{Total Time}}$.Zio, E. (2009). "Reliability engineering: Old problems and new challenges." Reliability Engineering & System Safety, 94(2), pp. 125–141.DOI: https://doi.org/10.1016/j.ress.2008.06.002Reference: Section 2.1 defines availability as "the probability that the system is operational at a given time $t$." The practical, time-based calculation for this is consistently represented as the ratio of operational time (total time minus downtime) to the total time over a given interval.