New to FreeNAS, backup question

Hello all, I have a new freeNAS box (11.1_U2) with 4, 1 TB drives that are holding plex data. I would like to have a second copy/backup of the data to a single 5TB drive that is an empty drive in another server (Hyper-V server 2016). I can think of several ways to attack this. I could setup a second FreeNAS on Hyper-V and replicate the data. I could potentially use Rsync and copy the data. I could do something else when you convince me that your solution is superior :-)

How would you approach this?