You put the 2 TB drive somewhere else (at a relative's) and keep it updated regularly via network.
That's my set up (but with a bigger drive).
At home, I have the master copy of the data on my file server. Then I have backup #1 that is in the same location and backup #2 that is in a different location.
Both #1 and #2 get updated at night with a "timemachine-like" backup system based on rsnapshot. The network traffic goes over ssh.
Remote backup system #2 cost a UPS, a RaspberryPi and an 8 TB drive, which is about ~$250-$300 total.
The initial sync is best done locally of course, but deltas can generally easily go over network at night.
Cheap, reliable, and (relatively) easy (if you're a geek, that is).
The name escapes me right now, but basically you had to add "friends" in the software, then dedicate a certain amount of HDD space to it. It would then back up your files to your friends' computers, and theirs to yours. Backups were encrypted so your friends wouldn't be able to see your files.
It was a super neat idea, I wish I could remember what it was called so I could see if they're still around...
Both use rsync-style deltas to only send changes, but they use a content-addressable scheme like git so renames are a small metadata change record.
Also, both offer ftp and fuse interfaces if you need to access an older backup.
I'm looking into using the incremental diff/snapshot feature of btrfs to implement a more efficient solution :P
https://en.wikipedia.org/wiki/Distributed_Replicated_Block_D...
Cheap and easy: buy a 2 TB drive and keep it at home. If some disaster affects your home -- flood, fire, burglary -- it can take out your data and its backup.
Cheap and reliable: buy a 2 TB hard drive and keep it somewhere else. Keeping the backup up-to-date means regularly bringing the drove home, updating it, and putting it back.
Easy and reliable: pay for a service like Backblaze that automatically backs up all your files to a remote server.
There are other benefits to services like B2 especially, namely being able to access your backed-up files from any device or location, or being able to link people to your files on a high-speed server.