"Unparalleled insights, in real-time, of everything happening on your Linux systems and applications, with stunning, interactive web dashboards and powerful performance and health alarms." (ib, 2017-08-27)
"Simple single-process process monitoring program written in C"
Dstat is a versatile replacement for vmstat, iostat, netstat and ifstat.
Glances is a CLI curses based monitoring tool for GNU/Linux and BSD OS
A list of questions/documentation/reports that any good service provider should have readily available!
PHP script to display information about the host being accessed. Displays things like uptime, cpu, memory, SCSI, IDE, PCI, network interfaces, ...
Open source tool designed to help network administrators collect, organize and maintain network documentation.
Pandora FMS is a monitoring Open Source software. It watches your systems and applications, and allows you to know the status of any element of those systems.
Iotop is a Python program with a top like UI used to show of behalf of which process is the I/O going on ... [evaluating] (the bi and bo columns of the vmstat 1 command).