The plain text server configuration files that had been used in ArcGIS Server 10.zero and earlier variations are now not a part of the server structure starting at model 10.1. You may discover related looking files in the configuration retailer, but these information are not supposed to be manually edited, and you may severely disrupt your server’s stability should you select to immediately modify them. Instead, you should use ArcGIS Server Manager to regulate your server properties. ArcGIS Server also exposes the ArcGIS REST API, which you can use to safely script modifications to your server configuration. See Logging in to Manager and Scripting ArcGIS Server administration to get began.