Linux

• Check for a particular file size. du -sh <filename>

Troubleshoot Error

1. Collect info and identify the problem
   • Slow response, high latency, unable to reach server, timeout
   • Check for recent change make to app or infra
2. Web server (infra) troubleshooting
   • See if processes is running
   • Check server health:
     • CPU/memory usage
     • Storage usage, disk I/O
     • Network traffic, latency, throughput
     • Error rate
   • Compare current performance metrics against baseline
   • Analyze pattern: look for unusual spike traffic, bandwidth hogs, malicious activities
   • Verify web server log and look for error
   • Review configuration setting. Ensure infra is properly configure
3. Application Performance Issue
   • Use Application Performance Monitoring (APM)
   • Help root cause analysis. Identify problem that could be cause by code issue, server performance, network latency
   • Check for response time, request rate, throughput, error rate, uptime
   • Check log for error
   • Check database query performance and number of connection
4. End-user troubleshooting
   • Access app from user browser. Check for response time and DNS issue

Find listening port on Mac

netstat -an | grep -i listen | grep 80
netstat -an | grep LISTEN | grep 80

Linux File System Explained