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What is SLA (service level agreement)?

An agreement between the provider and the user of an IT service that sets the quality levels, such as availability, response time, time to recover from failures and support hours, together with how they are measured and what happens if they are not met.

Japanese name: SLA(サービスレベル合意)

SLA (service level agreement) appears in 8 practice questions across 2 topics, including IT Service Management and Systems Audit, Software Development and Project Management.

Field: Software Development and Project Management

Try it: questions about SLA (service level agreement)

The SLA for a service specifies a monthly availability of at least 99.95%. A month is taken as 30 days, and planned downtime is included in the calculation. This month the service has already been down for a total of 15 minutes due to failures. How much more downtime is allowed for the rest of this month while still meeting the SLA?

  1. A6.6 minutes
  2. B21.6 minutes
  3. C36.6 minutes
Show answer and explanation

Answer: A. 6.6 minutes

A month is 30 × 24 × 60 = 43,200 minutes, and at 99.95% availability the allowed downtime is 43,200 × 0.0005 = 21.6 minutes. Since 15 minutes have already been used, 21.6 − 15 = 6.6 minutes remain. 21.6 minutes forgets to subtract the downtime that has already occurred, and 36.6 minutes adds it instead of subtracting it. An SLA should specify, as agreed between the service provider and the user, matters such as whether planned downtime counts toward availability and the measurement period.

To achieve the service levels promised to users in an SLA, an IT service provider agrees with the network operations department and other departments within the same organization on the content and level of the work each is responsible for. Which of the following is this agreement?

  1. ASLA (service level agreement)
  2. BA contract with an external supplier
  3. COLA (operational level agreement)
Show answer and explanation

Answer: C. OLA (operational level agreement)

IT services are delivered through the cooperation of several departments within the organization, such as the service desk, server operations and network operations, and of outside companies. To keep the SLA with users, OLAs (operational level agreements) are made with the internal departments that support it and contracts with external suppliers, fixing the level of the work each one is responsible for. The targets of the OLAs and contracts are set so that the SLA targets can be achieved.

SLA (service level agreement) in the explanations

Questions that mention SLA (service level agreement) (8)

  1. The SLA for a service specifies a monthly availability of at least 99.95%. A month is taken as 30 days, and planned downtime is included in the calculation. This month the service has already been down for a total of 15 minutes due to failures. How much more downtime is allowed for the rest of this month while still meeting the SLA?
  2. To achieve the service levels promised to users in an SLA, an IT service provider agrees with the network operations department and other departments within the same organization on the content and level of the work each is responsible for. Which of the following is this agreement?
  3. Which of the following is the most appropriate service level item to agree on with users in the SLA for a company's internal expense reimbursement system?
  4. The SLA for an internal system sets the service hours as 9:00 to 21:00 on weekdays (12 hours a day) and requires availability during service hours (the fraction of service hours during which the system was in operation) of at least 99.5%. Take a month as having 20 weekdays, and do not count outages outside service hours. Which of the following is the upper limit on the total outage time allowed within service hours in a month?
  5. The SLA for a cloud service defines monthly availability = (scheduled service time − outage time due to failures) ÷ scheduled service time, where the scheduled service time is the total time in the month minus the time of planned maintenance announced in advance. If the monthly availability is at least 99.9%, there is no refund; if it is at least 99.0% but below 99.9%, 10% of the monthly fee is refunded; and if it is below 99.0%, 30% is refunded. Take a month as 30 days. In one month there were 120 minutes of planned maintenance and a total of 40 minutes of outages due to failures. Which of the following is the refund rate for this month?
  6. An incident received by a service desk staff member was about to exceed the resolution target time set in the SLA. The staff member reported the situation to the service desk manager and asked for a decision on adding staff and on contacting users. Which of the following is this action?
  7. A system has an MTBF (mean time between failures) of 500 hours, and the availability target in its SLA is at least 99.5%. Assuming the MTBF does not change and calculating availability = MTBF ÷ (MTBF + MTTR), which of the following is closest to the maximum MTTR (mean time to repair) that meets the target?
  8. Which of the following is an appropriate activity of service level management?

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Related terms

Service desk Escalation MTBF (mean time between failures) MTTR (mean time to repair) Agile development Black-box testing Boundary value analysis Branch coverage CI/CD (continuous integration and continuous delivery) Critical path method (CPM)

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