I use a rotating set of external drives, as follows:
- As a Mac user, I let Apple's Time Machine do it's hourly backup thing -- it's the path of least resistance. I direct my Time Machine ("TM" hereafter) backups to a separate backup drive. In theory this could be an external, but I had 3 free drive bays, so I use an internal drive.
- I use SuperDuper to clone my TM backup drive to an external drive once a week. This external drive is not connected to my system except during the clone operation. The rest of the time the drive lives in the media-rated fire-box in the basement.
- Once a month, I swap the TM clone drive for it's mate that lives off-site.
The initial TM backup is my protection against shooting myself in the foot by deleting the wrong file or otherwise hosing my system. The usually-offline clone is my protection against serious hardware failure, theft of my entire computer system from the study, etc. It's also protected from house fire (as long as it isn't
too catastrophic) and isn't obvious for a thief to grab unless they do a careful search of the house. Meanwhile the drive that lives off-site is insurance against any catastrophe that levels my house, but not the entire city. (I figure that if the city is gone, I have bigger problems than preserving my data...)
I plan to switch to a mirrored raid with offline members for the TM backup drive once SoftRaid 4.0 is released. It'll provide a bit more redundancy with faster cloning to the off-line and off-site drives. I also plan to start cloning my boot drive similarly. Disks are much cheaper than my time.
Xenophon