Backup to external USB drive?

[preikin]

I'm new to using freenas. I'm in the process of setting up 2 freenas servers. I have 1 running and loaded data onto it. To provide extra protection from losing data, I would like to backup the data I stored on it to an external USB drive and keep it offsite.

I thought maybe I could do this with rsync. Is that what would be recommended? If I should use rsync then how do I go about mounting the usb drive? Currently when I plug it in, it shows up in the storage tab of the web gui. Does that indicate it automatically mounted? Should I format it as ext4? It is ntfs right now.

I've looked everywhere and can't find a guide on rsync to a usb drive with freenas. I would like to be able to view the files on any computer not just freenas. That's why I am trying to use something other than zfs snapshots onto a usb drive which is something I found a guide for.