CentOS Stream 9 – Common Problem 075 – Diagnosis and Fix

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

After a panic, no vmcore is written under `/var/crash`.

Environment & Reproduction

kdump service did not start or the reserved memory is too small.

Root Cause Analysis

Kernel `crashkernel=` parameter is missing or insufficient.

Quick Triage

Check `systemctl status kdump` and `journalctl -u kdump`.

Step-by-Step Diagnosis

Verify boot args with `cat /proc/cmdline` for `crashkernel`.

Solution – Primary Fix

Set `crashkernel=auto` or a specific size via `grubby –update-kernel=ALL –args=…`.

Solution – Alternative Approaches

Reboot and trigger a test panic only in a staging environment.

Verification & Acceptance Criteria

vmcore is written to `/var/crash//` after a forced panic.

Rollback Plan

Disable kdump if storage is constrained; rely on logs.

Prevention & Hardening

Allocate dedicated crash space and rotate vmcores.

Related Errors & Cross-Refs

Pairs with grub configuration and large memory hosts.

Related tutorial: View the step-by-step tutorial for centos-stream-9.

View all centos-stream-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Red Hat kdump documentation and analyze with `crash`.