https://www.youtube.com/watch?v=66KWuIxHU4E

System failure is not binary - your application may be slow, or restarting too often, or teetering on the edge of disaster. System monitoring is how you detect these issues - either before or after the fact. I show you how I scan my aggregated logs from multiple components for certain logged error conditions (e.g. hacking attempts). If serious ones crop up, an email alert is triggered. Next I demonstrate how to use Monit to get real-time stats on your system’s CPU and RAM usage. Following that I use another tool to graph my RAM usage patterns over the last week. Zooming out again, I introduce response time stats.