I went to Costco and bought a 1.5TB usb external drive. $59 USD. Because I live dangerously, I upgraded the pi2 to the latest Raspbian Jessie and eventually got my user name set up instead of the default ‘pi’. It makes everything easier in NFS to have the same user id (1000) on all NFS systems.
Then I had to get ssh whipped into shape. Always a mystery. Always a struggle.
I connected the SeaGate to my raspberry pi2 and after much horsing around with usb cables and even more horsing around with /etc/fstab and netatalk, it’s doing a Time Machine backup of the Mac Mini over enet to a pi with an external usb disk. Slow? Of course it is. Neither enet or USB is going to be fast on a Pi. 50% of one of 4 cores on the pi2. I also need to modify/add to the Linux backup scheme which uses rsync to backup to the pi2.
Having had to restore from backups before, I know what I should do buy there are constraints that in any scheme. Constraints that don’t need to apply get encoded into scripts and processes. Since I’m pushing around GB of data around, it takes time. A lot of time.