Service Level Agreement (SLA)
What Is a Service Level Agreement?
A Service Level Agreement (SLA) is a formal contract between a service provider and a customer that defines the expected standard of service to be delivered, the metrics by which performance will be measured, and the consequences when those standards are not met. SLAs establish mutual accountability by specifying in precise, measurable terms what the customer can expect and what obligations the provider accepts in exchange for the contract.
In IT services, managed services, and cloud computing contexts, SLAs define uptime commitments, response times for support requests, resolution timeframes by incident severity, data recovery objectives, and the remedies, typically service credits, that apply when the provider fails to meet the defined standards.
Core Components of an IT Service SLA
Service Description
A clear definition of what services are covered by the agreement, the scope of included support activities, and any explicit exclusions that define the boundary of provider responsibility.
Availability and Uptime Commitments
The percentage of time that a service or system will be operational, expressed as a monthly or annual uptime percentage. A 99.9 percent uptime commitment translates to approximately 8.7 hours of allowable downtime per year. A 99.99 percent commitment allows approximately 52 minutes annually. The difference between these figures has direct implications for business continuity planning.
Response and Resolution Times
Defined timeframes within which the provider must acknowledge and respond to support requests and separate timeframes within which those issues must be resolved. These commitments typically vary by incident severity classification: a critical outage receives a faster response commitment than a low-priority informational request.
Measurement and Reporting
How SLA metrics will be measured, who has access to performance data, the reporting cadence, and how disputes about SLA calculations will be resolved.
Remedies and Penalties
Service credits or other remedies that the customer receives when the provider fails to meet a committed SLA metric within a measurement period. Remedy provisions create financial accountability for SLA performance and give the customer recourse beyond simply accepting service quality failures.
Internal SLAs vs. External SLAs
External SLAs are contractual commitments between a vendor and its customers. Internal SLAs are agreements between IT departments or teams and the business units they serve, establishing the same kind of accountability within an organization without external contractual enforceability. Internal SLAs are an important governance tool for aligning IT service delivery expectations with business requirements.
Key Takeaways
- An SLA defines expected service standards, performance metrics, and consequences for non-compliance in a formal agreement between provider and customer.
- Core components include service description, uptime commitments, response and resolution times, measurement methodology, and remedies.
- Uptime percentages translate into specific annual downtime allowances that directly affect business continuity planning.
- Remedy provisions create financial accountability that incentivizes providers to maintain committed performance standards.
- Internal SLAs establish the same accountability structure within organizations between IT and the business units it serves.