[Johnny555]

The core data that I'd want to restore immediately if I lost my primary fileserver is only around 100GB or less

I have several TB's of other data (mostly photos, videos, etc) that I'm fine waiting for weeks or months for if needed, but if you're in a hurry, Backblaze will sell you a hard drive that they restore your backup to and mail it to you.

[skookumchuck]

At that point, one might as well just wind it off to a hard disk in the first place, then store it offsite.

[Johnny555]

Then I'd need multiple hard drives for redundancy, and I have to bring them back and read them regularly to make sure the data is all readable. And while I have a large amount of data that I rarely touch, I have a small amount that changes frequently, so I need to include that data in my off-site backup too.

Or I could just sign up for a cloud backup service, spend a month or so uploading my initial snapshot of data, and then backups are automatic and always offsite, replicated, and scrubbed. For $10/month.