Asciiroot / Linux operations
Linux troubleshooting guides
Start with evidence, understand what each check can and cannot tell you, and plan recovery before changing a production system.
These 6 focused guides are starting points, not a complete Linux reference or a verified diagnosis of your system.
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Linux service not starting: a systemd investigation
Investigate a Linux service that fails to start using systemd status and journal checks, then plan safe recovery and verification.
Linux memory pressure and OOM: an investigation guide
Investigate Linux memory pressure and possible OOM events using memory and kernel evidence, with container-limit and recovery checks.
Linux disk full: check space, inodes and recovery
Troubleshoot a full Linux filesystem with df space and inode checks, safe evidence collection, recovery planning and monitoring.
Linux DNS resolution failure: a safe troubleshooting guide
Investigate Linux name-resolution failures using getent and resolver status, then compare caches, upstream answers and affected clients.
Linux high CPU or load: distinguish the symptoms
Investigate Linux CPU pressure and high load by comparing process activity, CPU limits, waiting tasks and application impact.
Linux SSH permission denied: investigate authentication safely
Investigate Linux SSH permission-denied errors using authorized identity, listener and service-log checks without weakening security.
How to use these guides
These checklists combine curated operational guidance with links to relevant project or vendor documentation. A link is a pointer, not a live check, and the documentation for your installed version may differ.
We have not inspected your environment. Have a qualified administrator verify the commands, permissions, change approvals, backups and recovery plan before acting. Report a correction through the contact link below; do not send passwords, private logs or customer data.
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