SLOs, SLAs, and SLIs: putting numbers on "it kinda works"

Fri, 20 Feb 2026 00:00:00 +0000

In almost every company, there’s a magical phrase used to describe a system’s health: “it more or less works.” Translated into plain English: nobody knows how often it goes down, how many requests fail, or how much money is lost when it decides not to work. But hey, “more or less.”

SLI , SLO , and SLA are the grown-up version of that phrase. They’re the way to go from “I think it’s fine” to “this is what it handles, this is what we promise, and this is what’s at stake” — without having to fall back on the classic “trust me, I’m an engineer.”

SRE on I am Lino

SLOs, SLAs, and SLIs: putting numbers on "it kinda works"