Performance & Scaling
Bug Report
Everything slow, CPU idle, iowait at 60%: tracing disk saturation to a log compressor
Requests on a reporting server took ten seconds every morning while CPU sat mostly idle. iowait at 60% pointed at storage; iostat and pidstat pointed at logrotate compressing a 40 GB log on the same volume as the database. How we found it and moved the work off the hot path.