CPU Wait Time Indicating I/O Bottlenecks

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Resource ContentionUpdated Apr 29, 2025

High CPU wait time in apache_cpu_time suggests I/O or network bottlenecks rather than compute limitations. This often indicates slow disk operations, network latency to databases, or issues with external service dependencies.

Sources

Apache Tomcat Performance Monitoring: Basics and ... - Last9last9.io

Troubleshooting Tomcat Errors (And How to Fix Them) - OpenLogicwww.openlogic.com

Technologies:

Apache TomcatSymptoms of this issue are visible in Apache Tomcat metrics and logs

How to detect:

Monitor the wait component of apache_cpu_time separately from user CPU. Alert when wait time exceeds baseline thresholds. Correlate with apache_traffic, tomcat_size_rcvd, and tomcat_size_sent to identify network-related causes versus disk I/O.

Recommended action:

Analyze disk I/O metrics on the host system. Review database query performance and network latency to external services. Check for slow log writes by monitoring log file sizes and rotation. Optimize static content delivery and consider CDN for apache_traffic-heavy operations.