At home, I have about 1TB of data needs backup and update frequently.
The new data is currently copied to one hard-drive and mirrored to other hard drives. However, this is not safe, if there is user error in the 1st step, all other backups are destroyed.
What's the best solution that it can: - have multiple backup. Any single hardware failure won't destroy the data. - user error tolerate. For accident deleting, overriding data, nothing should be lost.
( version control system can be good, but they don't work with hard-drives. There is no local copy of the data. The data are collected from different places )
There is also sensitive data that only stays in these off-line hard-drives. It is physically disconnected from the web, so hackers cannot touch those data. For example:
On-line machine A (PC): - public photos
On-line machine B (Mac): - personal document
Off-line hard-drive 1 - Sensitive data - backup (version-control?) of A - backup (version-control?) of B
Off-line hard-drive 2 - mirror (version-control?) of 1