Is anyone using, in a production environment, New Relic for application or server monitoring? It seems to be in the same class of Pingdom and Zabbix.
More specifically, what kind of logs does New Relic produce? Its relevant documentation section does not say much. Do they use (or are compatible with) a third-party tool (e.g., Apache Log4J), or do they have their own log format and patterns?
If there is any open source log example from this tool, please provide a pointer.
Full disclosure up-front, I am a New Relic Developer/Evangelist.
The New Relic agents don't produce logs which you then would parse in a tool like Apache Log4J. The agent collects data from your application (trace details, database calls, etc) and sends that data to the New Relic hosted application. To use the agent, you'll just need to install it. You won't need to add any extra instrumentation code or configuration.
You then use the New Relic site to view and all the collected data, which you'll see things like performance graphs and slow transaction details. Unlike processes logs, you can get full stack traces and SQL explain plans for slow transactions.
The references to logs in the documentation are generally for troubleshooting issues with an agent.
**EDIT**
The Java agent can produce a log, starting with version 2.6.0. Turn on audit_mode in your config and you'll find the output in newrelic_agent.log. You can see a sample of the output in this gist.