Series
Application and service troubleshooting
Why is a server, service or app slow, down or erroring, and how do you fix it?
In short
A service crashed, nginx answers 502, the load average is high, a port is taken, memory is gone: how to find the cause from the real signals on the box and the command that fixes it.
Guides
Start here: each answers one question in full, with the commands.
Why is my server slow? A 10-minute checklist (CPU, memory, disk, network, app)
Read →How do you monitor Laravel servers in production?
Read →Can AI actually fix server issues, or does it just tell you what's wrong?
Learn what AI-driven server remediation actually does, what to look for, the honest trade-offs, and how automated fixes compare to manual ops.
Read →
How-tos and field notes
One problem each, written to be run through in the next ten minutes.
How to safely auto-restart a downed service
Read →How to debug a service that keeps crashing and restarting (systemd, Docker, PM2)
A service in a restart loop: read the exit code, find the real error in journalctl or docker logs, spot OOM kills and bad config, and stop the loop.
Read →Find and Kill the Process Using a Port on Linux (One Command)
One ss command shows the PID holding any port in a second. Copy-paste ss, lsof and fuser examples, and how to kill it safely with fuser -k 8080/tcp.
Read →How to Fix High Memory Usage on a Linux Server
Linux server running out of memory? Learn how to diagnose and fix high memory usage with real commands — before it takes down your app.
Read →How to Read and Make Sense of Nginx Error Logs
Learn to decode nginx error logs fast — understand severity levels, common errors, and the commands that actually help you fix production issues.
Read →How to Reduce Nginx 502 and 504 Gateway Errors
Practical steps to diagnose and fix nginx 502 and 504 errors — from upstream timeouts to worker limits — before they wake you up at 3am.
Read →nginx worker_processes and worker_connections: how to tune them, with numbers
What worker_processes auto really does, how to size worker_connections from ulimit -n, the worker_rlimit_nofile trap, and how to tell you set them wrong.
Read →What to Do When a Linux Server Load Average Is High
High load average on your Linux server? Learn how to diagnose the real cause and fix it fast — with practical commands and clear steps.
Read →
Free tools and references
No signup. Paste, check, read.