📖 ~1 min read
Table of contents
Symptom & Impact
After panic, system reboots without vmcore, blocking root-cause analysis for critical crashes.
Environment & Reproduction
On RHEL 8, kdump is enabled but no dump appears in configured crash directory after test panic.
Root Cause Analysis
Missing crashkernel memory reservation or inaccessible dump target prevents capture process completion.
Quick Triage
Check systemctl status kdump, grub kernel args, and journalctl for kdump initialization failures.
Step-by-Step Diagnosis
Verify crashkernel parameter, dracut kdump image, and storage/network target availability for dump writing.
Solution – Primary Fix
Set appropriate crashkernel value, rebuild initramfs if needed, restart kdump, and run validated test capture.
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Solution – Alternative Approaches
Use remote dump target via SSH/NFS where local disk capacity or reliability is insufficient.
Verification & Acceptance Criteria
Test panic produces vmcore and metadata, and dump location remains accessible after reboot.
Rollback Plan
Revert kdump config and kernel args to prior state if memory pressure affects normal workloads.
Prevention & Hardening
Schedule periodic non-production kdump validation and monitor crash dump storage utilization.
Related Errors & Cross-Refs
Related to bootloader misconfiguration, dracut build errors, and SELinux restrictions on dump paths.
Related tutorial: View the step-by-step tutorial for rhel-8.
View all rhel-8 tutorials on the Tutorials Hub →
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
Use RHEL 8 kdump operational guides and Red Hat crash analysis recommendations.
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