[smoyer]

We're currently using Splunk (and may move to the ELK stack) for logging, but some types of "application events" are really more useful as metrics. We're using Ganglia for those metrics and limiting application logs to actions that are needed for audit purposes and for warning and error-level application problems.

Using a system like Ganglia (or the Etsy inspired statsd) is an important idea since the OP's original question included how to limit the size of logged data. These systems provide a natural way to aggregate data.