What is SLA?

#What an SLA contains

An SLA specifies the metric, the threshold, the measurement method, and the measurement window. It also defines exclusions: scheduled maintenance, force majeure, and failures attributed to the customer's own systems commonly do not count.

The defined consequences distinguish an SLA from a service target with no associated commitment. Service credits are common in commercial agreements, usually a percentage of fees refunded on a sliding scale by how far the target was missed. The exclusions and measurement method often matter more than the headline number.

#Why SLAs matter

An SLA converts reliability from an engineering aspiration into a commitment with defined consequences.

• Enforceable expectation: users have recourse rather than only complaints.
• Risk pricing: the provider prices the cost of missing the target into the agreement.
• Investment justification: exposure to those consequences funds reliability work.
• Procurement comparison: a common basis for evaluating vendors.

#Limits of SLAs

Service credits may compensate only a limited portion of a customer's actual loss and may also limit the provider's contractual exposure. A customer whose business was down for six hours may receive a small percentage of one month's fees.

Exclusions can also hollow out the commitment. An SLA excluding maintenance windows, degraded performance short of unavailability, and any failure in a dependency may guarantee relatively little in practice while displaying an impressive number.

#SLA vs SLO

An SLO is a measurable service-level target. An SLA adds an agreement with users and defines what happens when the included service levels are met or missed.

Teams often set an internal SLO that is stricter than an SLA target to create an operating margin before customer-facing consequences are triggered. This is a common risk-management practice rather than a defining requirement.

#Key takeaways

• An SLA creates an agreement with users and includes consequences; those consequences are not necessarily financial.
• It specifies metric, threshold, measurement method, window, exclusions, and remedy.
• Exclusions and measurement methodology frequently determine the real commitment more than the headline number.
• Organizations often set internal SLOs stricter than SLA targets to preserve an operating margin.

#Frequently asked

What is a typical SLA remedy?

Service credits are common in commercial cloud agreements, but remedies vary by provider, service, contract, and severity of the miss. State the applicable remedy from the actual agreement rather than relying on a universal percentage range.

Why set the SLO stricter than the SLA?

To create margin. If they are equal, the first signal that something is wrong can be the moment consequences are triggered.

Do internal teams need SLAs?

SLOs are often sufficient internally, since there may be no meaningful remedy to enforce between teams in the same organization. Clear expectations matter more than contractual language.

#Sources

• Google SRE: service level objectives