Just for sh!ts and giggles, I connected a USB hub to the USB3 port on my Linksys WRT3200ACM router running OpenWRT to see what would happen. Hey, I live on the edge.
Somewhat surprisingly, it works. LuCI couldn’t see the new drive; but I was able to initialize, partition, and format an 8TB Seagate Exos drive in the shell, after which it was available for use as a shared drive in LuCI. That’s in addition to the existing 4TB Seagate IronWolf drive.
So now I have 12TB of storage coming off the router, which I use for backups of backups as well as easily-replaced stuff like downloads that I want to make available across the LAN.
Anything actually important that’s not in itself a backup of a backup is backed up to B2 using GoodSync, thus also making it available remotely on my laptop using Mountain Duck in addition to backupping it.
I decided to try that as opposed to buying another Tiny PC to use as a NAS controller, and saved a couple hundred bucks in the process.
Life is good.
Richard
I like the WRT3200ACM for OpenWRT so much that I recently bought a spare. Which reminds me, I have to take it out of the box and test it while the return window is still open. I’ll probably pre-configure it, as well.
There also are a lot of mini-PC’s made by companies like Qotom that can run OpenWRT, and some builds specifically designed for those kind of boxes. I have no experience with any of them.
I had serious doubts about the router’s ability to handle both drives; but the first task was copying about 1.7TB of data from the 4TB drive to the new 8TB drive, and I got peak transfer rates of ~ 150MB/s. Not too shabby for USB.
Richard
Some people’s NAS are worse than that. 
Also taking into account, its based on a router with USB attached drives, then thats pretty good. 
Yeah, I’m happy with it. Like I said, I have another still in the box as a spare.
It’s also really easy to migrate from one to the other. It takes about ten minutes. I’ve just been to busy with other stuff lately. It’ll get done.
Richard