One of the articles I really enjoyed reading recently was Quality Control by Last.FM. In the spirit of this article, I was wondering if anyone else had favorite monitoring setups for web type applications. Or maybe if you don't believe in Log Monitoring, why? I'm looking for a mix of opinion slash experience here I guess.

+2  A: 

We get a bunch of email/pager alerts from an older host/app/network monitoring environment that get gradually more abusive depending on severity of the problem/time taken to respond. Fortunately we all have thick skins and very broad senses of humour. :)

+2  A: 

We use log4net, and normally write both to log files and the database. However, when we've been tracking down a particularly difficult problem, we've enabled the email appender, so that critical log messages went straight to a developer's email account. This allowed us to figure out what was happening more immediately.

In addition, our infrastructure team has several tools they use to monitor system uptime, event logs, etc., to give them early warning when something is about to go down. We've also helped them implement custom monitoring scripts that test specific functionality of our code.

Corey McKinnon