Problem:
The client reported sudden high CPU utilization on their RHEL 7.5 Nexus server. Despite disabling tasks and restarting the server, the issue persisted. Logs indicated that the Nexus process was the top contributor to CPU utilization.
Process:
Steps and measures undertaken to investigate the issue:
- Requesting Information: Furnished JVM logs, Nexus application logs, and operating system logs as requested by the expert to facilitate deeper investigation.
- Suggestions Disabling Tasks: Disable all tasks on the Nexus to isolate the root cause of frequent restarts and high CPU utilization.
- Additional Information Request: Share disk space status, process overview, list of processes, installed packages/services, and application logs to aid in diagnosis.
- Maintenance Activity: Planned a maintenance activity on the server to bounce the application for further analysis.
Solution:
Suggestions provided to the client for resolution and next steps:
- Enable Database Backup: Expert recommended enabling the “Database Backup Weekly” task for reference before further troubleshooting.
- Backup and Maintenance: Advised the client to make backups before performing maintenance tasks, such as stopping and restarting the Nexus service and executing Repair and Compact BlobStore tasks.
- Investigate Task Execution: Suggested investigating why tasks are still being executed despite being disabled, emphasizing the importance of backups to mitigate data loss risks.
- Review Logs: Asked the client to provide logs before and after stopping Nexus, as well as examples of executed htop commands with CPU metrics for analysis and comparison.
Conclusion:
Deeper investigation revealed frequent rebuild tasks and anomalies in task executions, possibly due to unauthorized access. The resolution plan involved backup tasks, manual execution of maintenance tasks, and monitoring for performance improvements. Ongoing collaboration and analysis are required to address the root cause and ensure stable server performance.