What is Client export/ import pre-requisite?

A lot of these decisions depend on the size of your source system. While a client copy is taking place you should not have anyone performing updates. I have never locked the users, when doing a client copy over a weekend, but if you think someone might logon you might have to lock them. A client export is quicker than a Remote client copy, for access to the source system. For a client export make sure you have plenty of space in the Transport Folder '<Drive>:\\usr\\sap\\trans' for the export data files. If you use the Client Export method do not forget to use Tx SCC7 after the import is complete in the target system/client