Monit vs nmon

Monit is a free, open-source utility for managing and monitoring Unix systems, available for Linux, macOS, and self-hosted deployment. It watches local daemon processes and can restart a stopped process or stop one using too many resources. It checks files, directories, and filesystems for timestamp, checksum, or size changes, and tests TCP, UDP, and Unix domain sockets using protocols such as HTTP and SMTP. Scheduled program or script checks can trigger actions or alerts based on exit values. Monit tracks CPU, memory, system load, and network interfaces, and sends customizable error alerts to syslog or its own log. Its HTTP(S) interface displays service status and allows process control and monitoring changes. It works with init, upstart, and systemd, can use existing run-level scripts, and can run as PID 1 in containers. The maker says it uses statically linked OpenSSL 3.5.7 and dynamically linked PAM support.

nmon is a free Linux tool for systems administration, tuning, and performance benchmarking. It collects system information and presents live readings in a terminal through a curses interface. Keyboard controls let operators turn individual data categories on or off. The display can include CPU, memory, network, disks, filesystems, NFS, top processes, and, in the Linux version, resources and processors. Captured readings can be written to a comma-separated file for later analysis or longer-term recording. nmonchart converts output into webpage graphs, while nmon Analyser loads files into Excel and creates graphs. njmon injectors can add JSON data to InfluxDB and Splunk, with real-time graphing through InfluxDB and Grafana. Binaries are listed for POWER, x86, x86_64, mainframe, and ARM Linux. Unsupported distributions require compiling with GCC and the ncurses development library. The Linux project is GPLv3; AIX nmon is integrated into topas and is not open source.