Are you working to put together a migration plan for the transition to ArcGIS for Server 10.1? Because there are significant changes in the software architecture at ArcGIS for Server 10.1 a number of hints and tips have been put together to help you through the process.

Good to Know’s

• At ArcGIS Server 10.1, service configuration files from previous versions will no longer work. (At previous releases, service configuration files would remain valid.) Version 10.1 uses a different mechanism for map services called the Service Definition (SD), which is not a text configuration file as it was in previous versions. Previously created map caches will remain valid.
• ArcGIS Server 10.1 no longer uses SOM and SOC.  At 10.0, you had to manage accounts for each, but at 10.1, you’ll only have to manage one account.
• The concept of a distributed installation with multiple SOC machines attached to one or more SOM boxes is also going away. Each GIS server is its own installation. GIS server machines and services may be clustered together using tools available in ArcGIS Server Manager to offer better computing power, but each ArcGIS Server machine is effectively autonomous.
• There is no longer a differentiation between the Java and .Net versions of ArcGIS Server.  Now it’s just ArcGIS Server. The product installs with its own application server; this server should be dedicated to ArcGIS Server and nothing else. Esri has created applications, called “Web Adapters,” that link your current server of choice (IIS or a J2EE application server) to the GIS server instance. These applications are small broker components that basically forward requests from your web server to the internal server used with ArcGIS.
• When you create an administrative connection to ArcGIS Server 10.1, you’ll have the option to package and copy data in the Service Definition and push the whole package up to a GIS server. This means that an SD is portable – a user in one location can create a service definition and ship it to the GIS server owner without having to worry about an account having access to data in the remote location.