After upgrading to ArcGIS Server 9.3, using Data Appliance version 1.x, some map services cannot be started, whereas other map services can be started properly.
All of these map services used to work properly with ArcGIS Server 9.2
When starting a map service in Server Manager, the following error message is returned:
"Unable to Start service. Error (Server Object instance creation failed on all SOC machines. Server Object instance creation failed on machine <server_name>)."
When creating a new map service in ArcCatalog, a dialog window with the following error message is returned:
"Server Object instance creation failed on all SOC machines. Server Object instance creation failed on machine <server_name>."
When ArcGIS Server 9.2 was released, the only image format supported for map caches was PNG24.
In ArcGIS 9.2 Service Pack 1, support for other image formats was added including JPG, PNG8 and PNG32. When these new image formats are supported, the XML configuration file (conf.xml) for map caches was modified to add new optional tags indicating the image format (TileImageInfo, CacheTileFormat, CompressionQuality). Some of the services on the data appliance were PNG24 and did not require an update to the configuration file, as ArcGIS Server 9.2 does not require these new tags in the conf.xml files.
When ArcGIS 9.3 was released, the new tags were required. Consequently, map services with the original 9.2 release config files no longer work correctly.