Riemann aggregates events from your servers and applications with a powerful stream processing language. Send an email for every exception raised by your code. Track the latency distribution of your web app. See the top processes on any host, by memory and CPU. Combine statistics from every Riak node in your cluster and forward to Graphite. Send alerts when a key process fails to check in. Know how many users signed up right this second.

Observium is an autodiscovering SNMP based network monitoring platform written in PHP which includes support for a wide range of network hardware and operating systems including Cisco, Linux, HP, Dell, FreeBSD, Juniper, Brocade, Netscaler, NetApp and many more.
Observium has grown out of a lack of network monitoring platforms which are both simple to manage and pleasant to use. It is intended to provide a navigable interface to the health and performance of your network. Its design goals include collecting as much historical data about devices as possible, using as much auto-discovery as possible with little or no manual intervention, and having a very intuitive interface.