MalVeauX,
I see a lot of in-depth discussions, and although I didn't read it all, I get the jest of it and see your somewhat in the same spot I was in while deciding my backup plan. Here is what I have done.
I have Three TruNas servers. Two full-time full-blown servers and a third built from previously used hardware layered with odd-sized storage.
My first NAS - which is the main server I call "Moses" is built from all-new hardware running an array of eight 4TB drives and houses two Pools of Datasets.
My second NAS - is a backup of the first with an array of six 8 TB drives in one pool. This server is set up with full replication of the first server on a nightly basis on most datasets and an hourly replication on two datasets that store our synced via synching data from Workstations. The replication only happens during business-type hours.
The third NAS - is a Long-Term disaster recovery backup - named Crack-R-Jack. This server has roughly three times the storage as the first server, and will only be turned on for a brief period every six months. It is located in another building away from servers one and two. After turning this server on, I modify its replication tasks to replicate in an unused area of the storage. Once that replication is finished and I am comfortable that all the data has been copied, I disable the replication tasks, wait a few days then power off the computer.
All the replication is done over a VLAN using the second NIC in all boxes, using a 10.100.XX.XX address, thus not taking up bandwidth.
Crack-R-Jack came online a week ago for the first time, and I have been verifying data and am ready to shut it down until July.
Why did I choose this setup? I don't like swapping hard drives to ensure I have relevant copies of my data. I find it easier and safer to keep A copy of the data than attempting to de-duplicate my files later on down the road. I keep all my data on the server in a recoverable fashion. If my two NAS servers were destroyed in a fire, I would only lose no more than six months of stuff, not the pictures and audio files of my family that have passed.
How about cloud storage? I don't have deep pockets to throw money at someone every month for something I can store on-prem myself.
The pictures I take on my phone are stored in the iTunes cloud. The pictures my children send me are stored similarly. My servers are in another building from my house on my property.
Also, I use the KISS method - Keep It Simple Stupid! Speaking to me - not someone else.
Happy Trails!
L