Free server monitoring solution which uses InfluxDB for data storage and Grafana for visualization of metrics. The solutions has a server part running on one host, and then one or more agent running across your landscape. Plugins exists for basic metrics and you can extend by writing your own plugins.
The server runs on Linux and AIX. Agents can be installed in Windows, MacOS, Linux and AIX. There are extra processor metrics for IBM Power (AIX and Linux).
More information at https://git.data.coop/nellemann/sysmon
