Raymond Ops

Sep 4, 2026 · Operations

CPU 100% at 3 AM: Complete Troubleshooting Guide with Real Incident Analysis

This article provides a step-by-step guide to troubleshooting CPU 100% incidents in production, covering Linux CPU metrics, Java GC and thread analysis with jstat/jstack/Arthas, system-level tools like perf and flame graphs, and a detailed case study where MySQL backup-induced replica lag triggered cascading Full GCs and CPU saturation.