Hi,
See there can be different cause of it.
Network performance,Amount of data , database performance, Stats on db side..
How many clients you have in the target system. If one only why don't you go for system copy .
Hope we are talking about SAP_ALL profile. But most ly it looks like the data copy is taking time . Did you check the test run how many resources are required for the copy.
118823 - CC-ADMIN: Size of a client
1900110 - Client copy takes too long at post processing program RSSOUSCO_FOR_CC
As i am not aware of most of the info please check the logs for client copy alos.
Thank
Rishi abrol