What are some alternatives?
When comparing Linux Dash and Nagios, you can also consider the following products
Netdata - Monitor everything in real time – for free
Zabbix - Track, record, alert and visualize performance and availability of IT resources
eZ Server Monitor - eZ Server Monitor is a script for monitoring Linux servers.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Icinga - Icinga is a fork of Nagios and is backward compatible.
Grafana - Data visualization & Monitoring with support for Graphite, InfluxDB, Prometheus, Elasticsearch and many more databases