I'm getting really frustrated trying to do something that seems like it should be easy: I want to set-up a nightly recurring backup, which simply maintains a 1:1 mirror of my shares (docs, pics, videos) on an external removable USB HDD.
The problem is, no matter how I set-up my backup job in Backup Central (ADM v5.1.4.RL21), the job NEVER removes files from the USB backup volume which have been deleted from the NAS. If I delete a file from the NAS, it remains forever on the USB backup. If I rename a file on the NAS, or move a file, a new file is created on the USB backup reflecting the file's new name or location -- but the old files remain there, also.
Which is a total mess. This behavior will fill-up my USB Backup-drive with needless copies of files, and will also prove extremely confusing to sort through in the event that I ever need to rely on it as a backup.
How can I make the NAS maintain a 1:1 mirror of my shares on a USB Backup Drive, preferably maintained on a nightly basis?
=== FURTHER DETAILS ===
I have the AS5404T. It contains 2 (two) 14TB Seagate Ironwolf Pro NAS drives. These drives are housed in bays 1 and 2, and they're set-up in a Raid 1 array, where the two drives mirror each other for a measure of data-safety/fault-tolerance.
There are four SMB shares configured. Let's call them:
PicsVids
CreativeArchives
MoviesTV
MyDocs
These shares are all working well, and I can access them from my PC, my laptop, and my phone -- both at home, and over Tailnet VPN when I'm away.
I'm attempting to back things up to two 22TB Seagate Expansion USB HDD's (5400-speed), which are both ext4-formatted. The idea is, I will have only one of these drives connected at a time. A nightly backup should run, maintaining a mirror of my SMB Shares on the connected USB drive. Once a week, I swap the drive out with the other one, so that I always have one connected and one disconnected. I do that so that, in the event of a power-surge that wipes out everything, I'll have only lost a week's worth of data at most.
I've tried configuring my backup job various ways in Backup Central -- both as "multiple items to single location," and as "one on one folder backup." I've tried both with "Archive Mode" selected and deselected. Google Gemini told me I should deselect an option called "Keep extra files at the destination" -- but that option does not exist.
Out of the job-options, the only one I've played around with is "Archive Mode." And while having that option de-selected does DRAMATICALLY increase the time it takes for a backup to complete -- to the degree that I'm fairly sure that with Archive Mode de-selected, it's actually doing a complete backup of every file every time, rather than just backing-up changes -- in either case, the job fails to delete files that were deleted since the last time the job ran.
I've left all the other options deselected in every case, since none of them seem relevant:
Support sparse files replication
Support symbolic link replication
Eject USB device when backup completes (I don't want it ejected)
Mission Mode (I don't want the job to terminate after a certain time; I want it to finish)
Anyway, any help in this matter is appreciated. I can't believe it's been such a tough nut to crack. I feel like, for most home-users like myself, this would be the preferred way of making backups. But shoot, maybe I'm a weirdo?