I just installed wowza 3.0.3. We are using sawmill to harvest wowza logs for reporting. And we have many clients that use our service. Therefore, we had been using corresponding applications in wowza server. For sawmill, we use x-app to differentiate between different applications. But on this link
http://www.wowza.com/forums/content.php?126-Using-Sawmill-to-analyze-Wowza-Server-log-files it tells us to use stats file instead. I am using access file because it has x-app field on it.