Hi Charles,
usually I see another architecture when working in the cloud (see
http://www.delphix.com/solutions/cloud-migration/ for example) with consequently benefits as (see replication on the user guide documentation):
- moving compressed data
- moving encrypted data (even though you use a VPN connection)
- remote VDB provision
- replicating data (for Disaster Recovery)
- faster syncing
However, if you want to link your 5TB sized source DB directly to the Engine in the cloud, you have to keep in mind that the first snapshot will be full: all block data of your DB will be transfered over the net. So the time to complete the first snapshot will depend strongly on the bandwith available on your VPN connection: it will be the bottleneck.
Regards.
Gianpiero