Service Level Agreement

## The "Contract" **SLA (Service Level Agreement)** is a business/legal contract. It says: "If we are not reliable, we will pay you money." ### SLA vs. SLO * **SLO (Internal)**: "We want to be up 99.9% of the time." (Result: Team unhappy if missed). * **SLA (External)**: "We promise to be up 99.5% of the time." (Result: Lawyers involved if missed). ### The "Buffer Zone" Wise teams set their **SLO** higher than their **SLA**. * SLA: 99.5% (Allows 3.6 hours downtime/month). * SLO: 99.9% (Allows 43 mins downtime/month). * **Gap**: This buffer ensures you get alerted and fix issues *before* you owe customers a refund.