Piwik is an awesome tool. But today I'm only using their JS Tracker to send requests to a pool of nginx servers. The event logs are parsed with Fluentd and saved in a mongodb instance. After that, a proccess do some aggregations and put in my postgresql (app db).

We have this setup because we run our custom and specific analytics for a lot of clients.

Do anyone have a similar setup and have some experiences or hints to share?