One of the benefits of switching your Rails app to use SysLog is taking advantage of your OS’s system-wide logging, as well as having finer grained control over how to process your log messages. For example, you can split the logs up based on Rails app, mongrel process, or even by app server if you’re using remote syslog.
[...]
...and now we’re using SysLog we can use Eric’s other tool, ProductionLogAnalyzer, to identify performance bottleknecks of our application. Geoffrey Grosenbach (aka topfunky) wrote a Hodel3000CompliantLogger if you want to use this tool without SysLog).