1) Create new replication agent for other server.
2) Stop publish server you want to clone
3) take backup of crx-quickstart folder
4) put it on other server
5) Start publish 1 and then publish 2
6) once both the server started pending replication queue will get clear
Without down time
1) Create new replication agent for other server
2) Take online back up of publish 1
3) put online backup on server 2
4) restore online backup
5) start publish 2
6) All the queue pending at publish2 replication agent will get clear.
After the clone change disaptcher.any to add extra renderer.