Before uninstalling your current ArcGIS Server, make copies of the following files and place them in a stable, secure location. Although you won't be able to directly use these files to restore your services, they preserve a reference of the settings you had. These backups are also useful if the migration is interrupted or postponed.<ArcGIS Server installation location>\Support\Instance.log<ArcGIS Server installation location>\server\system\Server.dat<ArcGIS Server installation location>\server\system\ServerTypes.dat<ArcGIS Server installation location>\server\user\cfg (all folders and files beneath this location)C:\inetpub\wwwroot\ArcGIS\Services\web.config (If necessary, adapt this path to your own web server's root location and your ArcGIS Server instance name.)