Copying a website using SSH command line (method for experienced users)
Copying the files using a compressed archive file method
Copying a large number of individual files using FTP can sometimes be unreliable. If you have command-line access to the both source and destination systems then you can create a compressed archive file containing all the files on the source system, then transfer that single file to the destination system where it can be decompressed.
Copying the database with MySQL command line method
REF: https://docs.joomla.org/Copying_a_Joomla_website