120GB is a lot of data to transfer to the internet on a regular basis: look to your connection speed (specifically the upload speed) and work out how long it will take, on average, to transfer it.
If you assume ten bits per byte instead of eight, it both makes the math easier and allows for the packet overhead reasonably well.
So if you have a 20m bit per second upload, that's about 16.6 hours:
120E9 * 10 = 1.2E12
1.2E12/2E6 = 60,000 seconds
= 1000 minutes
= 16.666r hours.
And that's pretty much a best-case scenario @ 20mbit/sec upload.
How often are you going to do a full backup? :laugh:
I backup the backups of essential data to the internet, but even then I keep the total below 10Gb to make sure it takes a reasonable time.
Even Google write data to an array of HDD's and physically ship them round the world - they do it so often they even have a name for it: FedExNet