1. All of the iControl methods will only effect the running configuration. You must manually call the System.ConfigSync.save_configuration() method to flush the running configuration in memory to disk in the bigip.conf and bigip_base.conf files. The reason we did this was due to the time overhead that each save takes. If we persisted every iControl call to disk, if you were trying to make many consecutive iControl calls, it would take forever. Back on the 4.x platform when you could only set the state of one object at a time, we had a customer trying to update 1000's of virtual servers with one app. If we introduced several seconds into each call, their app would have taken a long time to complete.
2. For external data groups, you must use the System.ConfigSync.upload_file() and download_file() methods and treat the external classes as remote files. You manipulate the contents locally, and then upload the file to the server. From that point, you can use the *external_class* methods in the LocalLB.Class interface to manipulate the external class as a single object.
3. Yes.
-Joe
Employee