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NIST NICE K0741 NIST NICE K1222 CompTIA Security+ 5.3 NIST NICE K0872 NIST NICE K0873
TechKnowSurge Catalog Interactives Availability and SLA Calculator
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Availability and SLA Calculator

Work out a service's availability from its outages, then check it against the SLA: the period it is measured over, maintenance windows and credits.

⚑ Complete this interactive to capture a CTF flag worth 5 points.

About this interactive

Availability is uptime as a share of the total time: uptime ÷ total time, or (total time − downtime) ÷ total time, times 100. Measured as a percentage, it does not matter whether the period is a day or a year. The lesson's chart of nines turns percentages into allowed downtime: 99.9% (three nines, the common standard) allows about 8.76 hours a year; 99.999% (five nines, the gold standard) about 5.26 minutes. A service level agreement puts a number in writing, with penalties, usually credits, when the provider falls short. Three details change the answer: - The measurement period. The same percentage allows far less downtime per month than per year. At five nines, a year allows about 5.26 minutes, a quarter about 79 seconds and a month about 26 seconds. - Maintenance windows. Planned, announced downtime is usually excluded, so it does not count against the SLA. - Credit tiers. The lower the availability, the bigger the share of the bill handed back. In the lesson's own worked example the video says the system was down 2 hours and up 18 hours of a 24-hour day and calls it 75%; 18 of 24 hours up is 75%, which means 6 hours down, not 2.

What you'll learn

Aligned to

NIST NICE
K0741 Knowledge of system availability measures
K1222 Knowledge of system availability requirements
K0741 Knowledge of system availability measures
K0872 Knowledge of service management principles and practices
K0873 Knowledge of service management standards and best practices
CompTIA Security+
5.3 Explain the processes associated with third-party risk assessment and management.

Key terms

Availability
The assurance that systems and data are accessible and operational when needed by authorized users.
Service Level Agreement
SLA
A formal commitment between a provider and customer that guarantees a defined level of service uptime, including terms for compensation if the standard is not met.
Maintenance Window
A scheduled period defined in an SLA during which planned system maintenance may occur and brief outages are expected and permitted.
Three Nines
An availability standard of 99.9% uptime, allowing no more than approximately eight hours of downtime per year.
Five Nines
An availability standard of 99.999% uptime, allowing no more than approximately five minutes of downtime per year, considered a premium reliability target.
Downtime
The period during which a system, service, or component is unavailable or non-operational; it is measured against uptime targets defined in service agreements.

Topics

Availability Sla Incident Response Interactive Calculation

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