When iowait jumps to 80% and commands stall, this guide walks through the Linux I/O stack, explains key iostat metrics, and shows how to pinpoint offending processes with iotop, then uses blktrace, btt, fio, and bpftrace to diagnose and tune storage performance.
This guide walks you through a step‑by‑step, non‑disruptive workflow for diagnosing high disk I/O on Linux servers using built‑in tools such as vmstat, iostat, iotop, pidstat, lsof and the low‑level tracer blktrace, then shows how to interpret the data, identify common root causes, apply targeted fixes, and verify improvements with fio benchmarks and continuous monitoring.
This article details a systematic investigation of MySQL insert slowdown caused by disk I/O anomalies, describing log analysis, blktrace data collection, RAID controller firmware bugs, and the final resolution through firmware upgrade, providing practical guidance for database performance troubleshooting.
