Word to the wise-
To manage the statistics at 10.3, see the following help section 'Configure server statistics' at:
Working with server statistics—Documentation | ArcGIS for Server
There is a new usagereports resource accessed from the server admin directory that allows you to specify the compile period for statistics and file age. The defaults are 30 min and forever, respectively. Unless you have unlimited space, I would change 'forever' to a more reasonable time period...
Thanks
David
David Coley
Sarasota County GIS