Downsizing Without Downtime: An SRE's Guide to Safe Cost Optimization

Downsizing Without Downtime: An SRE's Guide to Safe Cost Optimization Tags: aws finops sre reliability kubernetes In Part 1 , I covered finding $12K/year in passive waste — abandoned VPCs, orphan log groups, stale WorkSpaces. Things nobody was using. That was the easy part. This article is about the hard part: actively downsizing infrastructure that's still running in production — without breaking availability. This is where FinOps meets SRE, and where most cost-cutting initiatives fail. I've seen teams blindly follow AWS Cost Explorer recommendations, downsize an RDS instance during peak hours, and trigger a 45-minute outage. The problem isn't the recommendation — it's executing it without an SRE mindset. The SRE Guarantee : Every optimization in this article passes through three gates: error budget protection, assured minimum downtime, and reliability over savings. See the series introduction for the full guarantee. If any gate fails, we don't proceed — no matter how much the savings