[sciurus]

Parts of it seem similar to Riemann (which receives events pushed to it and processes then), and parts of it seem similar to collectd (which has plugins to gather just about any kind of metric and push them to just about any kind of storage imaginable). Collectd recently gained the ability to do some aggregation, but it can't do the level of message processing that hekad does. Collectd also lacks the message routing capabilities of hekad.

If you're not familiar with collectd's capbilities, you can get a quick overview of the official plugins at http://git.verplant.org/?p=collectd.git;a=blob;hb=master;f=R...