A service level objective (SLO) is a key element of a service level agreement (SLA) between a service provider and a customer. SLOs are agreed as a means of measuring the performance of the Service Provider and are outlined as a way of avoiding disputes between the two parties based on misunderstanding.
There is often confusion in the use of SLA and SLO. The SLA is the entire agreement that specifies what service is to be provided, how it is supported, times, locations, costs, performance, and responsibilities of the parties involved. SLOs are specific measurable characteristics of the SLA such as availability, throughput, frequency, response time, or quality.
The SLO may be composed of one or more quality-of-service measurements that are combined to produce the SLO achievement value. As an example, an availability SLO may depend on multiple components, each of which may have a QOS availability measurement. The combination of Quality of Service (QOS) measures into an SLO achievement value will depend on the nature and architecture of the service.
In Foundations of Service Level Management (2000), Rick Sturm and Wayne Morris argue that SLOs must be:
- Attainable
- Repeatable
- Measurable
- Understandable
- Meaningful
- Controllable
- Affordable
- Mutually acceptable
SLOs should generally be specified in terms of an achievement value or service level, a target measurement, a measurement period, and where and how measured. As an example, "90% of calls to the helpdesk should be answered in less than 20 seconds measured over a one month period as reported by the ACD system". Results can be reported by the percent of time that the target answer time was achieved compared to the desired service level (90%).
The term SLO is deprecated in ITIL V3 to Service Level Target, not to be confused with Service Level Requirement defined in the service design.
Famous quotes containing the words service, level and/or objective:
“The man of large and conspicuous public service in civil life must be content without the Presidency. Still more, the availability of a popular man in a doubtful State will secure him the prize in a close contest against the first statesman of the country whose State is safe.”
—Rutherford Birchard Hayes (1822–1893)
“Nihilism as a symptom that the losers have no more consolation: that they destroy in order to be destroyed, that without morality they no longer have any reason to “resign themselves”Mthat they put themselves on the level of the opposite principle and for their part also want power in that they compel the mighty to be their hangmen. This is the European form of Buddhism, renunciation, once all existence has lost its “meaning.””
—Friedrich Nietzsche (1844–1900)
“No actual skeptic, so far as I know, has claimed to disbelieve in an objective world. Skepticism is not a denial of belief, but rather a denial of rational grounds for belief.”
—William Pepperell Montague (1842–1910)