It's possible, but I wouldn't like to trust my only backup to a single hard drive. And once you consider maybe two drives and/or possibly a NAS with redundancy, it again gets expensive.
Saying that, surely the bandwidth limitation is your upload speed - unless your parents have a rather crappy broadband service?
You could always prepopulate the drive(s), then do incremental backups.
Yeah that's exactly what I'd do. Fill with initial data and then nightly afterwards.
I've currently got
Main Home Server - with an amount of storage, maybe around 10TB
Storage server - currently with 2 x 14TB drives in a ZFS mirrored array.
Plan is to migrate the lot to the Storage server which will backup to itself. Somehow.
Then I wanted a copy off site.
I suppose the upload speed at parents isn't an issue for recovery, since if I wanted the full backup I'd literally go and get it.
Aye, I suppose that's the main advantage of an off-site backup at a location that you can physically access still.
I have a "backup to itself" system in place on my main PC at present incidentally. Backup hard drives (which are not mounted by default), script runs once a week to mount the drive, do an incremental backup then unmount it again. Process has worked well so far - combined with an external backup as well of course.
My PLEX disks are backed up every night to a duplicate set in the same box. My laptop and Mrs WmA's laptop do file history backups throughout the day to a Raspberry Pi and these disks are backed up with an Rsync to a duplicate set. Other bits of kit around the place are backed up/duplicated as well (plus I keep all my important docs and things on an Owncloud server). I suppose I really should look at something "off-site" even if it's some ethernet string and an extension running out to the shed.
It's honestly got me thinking, I have an old NAS (liberated from work) with 4.5TB capacity. Currently it sits on my desk and I do periodic backups to it. I'm considering running a network cable to the far loft corner of my garage and sitting it there. OK it's not really offsite, but would stand a much, much bigger chance of surviving either a fire or a burglary.
Well I'm saying goodbye to Virgin cable in a week, so what with all the cable-shuffling maybe I'll actually get round to doing something.