Mac mini Late 2012 OS 10.12 Sierra. I recently replaced fusion drive with a 1TB SSD and a 2TB disc Hdd as two separate internal drives. I restored using Time machine Backup from an external drive (which I curiously found to have been formatted Journaled Case Sensitive). I purchased a 5TB Seagate Backup+ Plus Hub external drive. As instructed I formatted it as Mac OS Extended (Journaled) as I usually do to set up a drive for time machine. It has been over 13 hours and it has only backed up 285GB of 1.6TB. I believe that using 3.0 hub should be much quicker. Yesterday after a similar event I stopped the BU and reformatted the drive and started the process over with stated results. Suggestions?
You mention that you thoughts a USB3 hub would be faster, do you have the Seagate drive connected directly to the Mac mini? Do you have anything connected to the USB ports on the front of the Seagate (the included USB hub)?