collectd

A daemon that collects system performance statistics periodically, and provides tons of plugins to store and analyze these values

     

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ConDep

ConDep is a open source infrastructure configuration and deployment DSL (Domain Specific Language) specifically targeted to (but not limited to) the Windows Server platform. If your familiar with tools like Chef and Puppet, ConDep does very much the same, but with native support for Windows.

     

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Instrumental

Instrumental is a real-time, high-scale application and server monitoring tool with intelligent alerts, a powerful query language, and free development accounts.

     

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Nagios Core

Nagios Core network monitoring software is a powerful, enterprise-class host, server, application, monitoring and alerting tool

     

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Statman

Statman makes it possible to instrument and collect statistics from your high-traffic production Erlang systems with very low overhead. The collected data points are aggregated in the VM and can be sent to services like Graphite, Munin, New Relic, etc.

     

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Zabbix

An open source, enterprise-class monitoring framework

     

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