SLA (Service Level Agreement)

SLAs establish mutual understanding between providers and customers about service expectations, creating accountability and a framework for measuring performance.

Why it matters

• Sets clear expectations for both parties.
• Provides remedies (usually credits) when service falls short.
• Helps customers evaluate and compare service providers.
• Creates incentives for providers to maintain quality.
• Essential for compliance and audit requirements.

Key SLA components

• Service description: What's being provided.
• Performance metrics: Measurable criteria (uptime, latency, throughput).
• Measurement methodology: How metrics are calculated and reported.
• Remedies: Compensation for failures (service credits, refunds).
• Exclusions: What's not covered (maintenance windows, customer-caused issues).

Related terms

• SLO (Service Level Objective): Internal target, usually stricter than SLA.
• SLI (Service Level Indicator): Actual measured metric.
• Error budget: Allowable amount of unreliability (100% - SLO).

Common SLA metrics

• Availability/Uptime: Percentage of time service is operational.
• Response time: How quickly the service responds to requests.
• Resolution time: How long to fix reported issues.
• Throughput: Transactions or operations per time period.
• Support response: Time to initial response for support tickets.

SLA calculations example

• Monthly uptime of 99.9% = Maximum 43.8 minutes downtime.
• If actual downtime is 60 minutes, SLA is breached.
• Remedy might be 10% service credit for that month.

Best practices

• Define metrics precisely to avoid disputes.
• Establish monitoring and reporting mechanisms.
• Review SLAs regularly as needs change.
• Understand exclusions and maintenance windows.
• Document escalation procedures for SLA breaches.
• Negotiate meaningful remedies that incentivize performance.