No, do not do anything with the small HDD's. If you want a backup drive, get another 4tb SSD - they're cheaper than anything you'd put the multiple drives into & will run without being plugged into power.
You do not want sync, you want backup. Sync means if you delete something, it's deleted from the HDD's as well. Or save over an existing file.
Data Hoarder
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
No, do not do anything with the small HDD's. If you want a backup drive, get another 4tb SSD - they're cheaper than anything you'd put the multiple drives into & will run without being plugged into power.
You do not want sync, you want backup. Sync means if you delete something, it's deleted from the HDD's as well. Or save over an existing file.
Mac or PC?