Chris Breen started the ball rolling by explaining Next up were and , each describing their personal backup plans. One theme that ran through all of these articles was that a lone backup is not sufficient. You should have at least two, ideally of different types (Time Machine, clones, cloud services, and so on).
For many Mac users, this is the equivalent of a dentist telling you that brushing your teeth is not sufficient; you also need to floss. And it's likely to be met with an equal lack of enthusiasm. After all, statistics have consistently shown that the majority of computer users have no backup plan at all. Two or three types of backups? Backups of backups? Forget-about-it!
But you shouldn't forget about it. I speak from personal experience. Multiple personal experiences. As one example, allow me to recount a recent incident that happens to involve one of the oddest and most distressing bugs I have yet to encounter.
A couple of weeks ago, while working with my Mac Pro, my Dock momentarily vanished. When it returned, most of its icons were gone. I had no immediate idea why this had happened. But I remained calm. I figured the fix was easy enough: go to the Applications folder and drag the desired icons back to the Dock.
I opened the Applications folder. It was at this point that I stopped being calm. My Applications folder was completely empty! Its contents had entirely vanished in less than a second. The missing files were not invisible, moved to another folder, dumped in the Trash, or otherwise recoverable in any way. They were gone--with a speed that I associate only with UNIX's fearsome rm command.
I need to backpedal briefly here. My Applications folder was not 100 percent empty. There was one file left: Adobe Updater. It's also true that I had been running the Updater just prior to the onset of the disaster. Am I suggesting that the execution of UNIX code in the Adobe update somehow erroneously triggered this data loss? Not with any certainty. This vanishing act has never happened to me before or since. And a Google search did not turn up any references that would support an Adobe link. Still, I have to wonder.
Regardless, the cause of the disappearance was not my main concern. My focus was on recovering the deleted applications. After breathing deeply for a few moments, I turned to the mirrored clone of my startup drive. Using this backup, I was able to restore all of my applications in less than one hour. Whew!
My fears were not yet entirely quelled. As I had no sure idea what had caused the disappearance, I did not know if or when it might happen again. My backup software, ( Macworld rated 5 out of 5 mice ), automatically updates my startup clone every morning. Suppose the Applications folder contents vanished again later in the day, when I was not so lucky as to be around to notice. Now imagine that SuperDuper dutifully backed up my drive at its next appointed time. All my applications would be gone from my startup drive--and its clone backup. This would be a true disaster--unless I also had a second backup, either via another clone or an alternative such as Time Machine.
Time Machine (or any versioned backup) best saves the day when you need to recover a file that was deleted too long ago for it to remain on a cloned drive. A clone backup is essential for those times when your startup drive completely fails.
Any single backup is better than none at all. But serious protection of your data requires more than one.