Thanks for the help, I would've never thought that would be the issue.
I'm mainly concered about the disadvantages the 512byte sectors would cause on a 6tb drive vs the 4k sectors. I've looked a bit online but all the info I'm getting is from 2010, so it'd be nice if I could get a more modern opinion. Also, most of the individual files on the server will be around 20-30gb, so I'm thinking 4k sectors might be better?
It seems the 4k sector trend began around 2011. How come its taken that much time for unRAID to get support?
I'm thinking for the time being, I should probably use a different os that supports 4k sectors, and then switch back to unraid once support arrives.