[sk5t]

We built our monitoring package at Zetetic to be extremely flexible about what events go where, with multiple levels of non-blocking filtering and routing, so that everything remotely interesting could go to SQL (with or without a durable local queue in front of it), and just very critical stuff could also go to a local embedded database / lpr / MQ / ZeroMQ publisher, etc. My preference is for decoupled ZMQ subscribers to handle anything very gnarly.

Internal errors in the monitoring software itself first surface in NLog, which could--but probably oughtn't--be configured to feed even more errors into the monitoring system; obviously this could create a terrible feedback loop if left unchecked.