yes - I do this all the time.
If you want to transfer from the TVS-h1288X to the TVS-h1688X, do the following. Setup a static IP on ethernet 5 or ethernet 6 of the TVS-h1288X - for this example - make it 192.168.2.4, subnet mask 255.255.255.0, MTU 9000. Plug that port into the TVS-h1688X either ethernet 5 or 6 (these are the 10G ports on these models) - make the port on the TVS-h1688X a static IP of 192.168.2.3, subnet mask 255.255.255.0, MTU 9000. Install Hybrid Backup Sync on both QNAP systems, and enable RTRR on the TVS-h1688X and enter a password. Create a folder on the TVS-h1688X that matches what you have on the TVS-h1288X. Now in Hybrid Backup Sync, select Sync, One Way Sync, enter the IP address of the TVS-h1688X which is 192.168.2.3, enter the password, and now select the SOURCE folder (on the TVS-h1288X) and select the DESTINATION FOLDER (the one you just created on the TVS-h1688X). Click SYNC NOW - and the transfer will start. Over the 10G network (even if it’s just a single Cat 6 cable from one QNAP to the other) - you will transfer at 1000 - 1100 MB/sec, and it will take 90 hours to transfer your 90 TB of data.
Bob Zelin