How to use top to monitor a server's performance.
Improve uptime with Monit Server Monitoring. Monit will watch you system around the clock, and respond to out-of-the-norm events by following your instructions.
Use the vmstat tool to monitor your system's virtual memory usage.
Graphite is an enterprise-level monitoring tool renowned for its performance on systems with limited resources. It stores numeric time-series data and renders graphs of this data on demand. This guide provides an introduction to the installation and basic setup of Graphite together with Grafana.