I'm a belt-and-suspenders guy when it comes to backups. All this began one day in the mid-1990s, when I lost a day's work on my PowerBook 100. From that day on, I have been extremely prudent about how I protect my data, and I currently use a multi-pronged backup approach, and even use multiple backups for important data.
What's connected to my Mac
I currently use a Mac mini, to which I have connected two 1.5TB external drives via FireWire 800. One of these drives is my media drive, which houses my very large music collection, some videos, and other media files. The second is a backup drive, with two partitions: one for a clone of my startup volume, and the other for other backups. I also have an AirPort disk connected to my AirPort Extreme, which is available via Wi-Fi for Time Machine backups. Finally, I have a disk dock connected to my Mac mini, in which I place hard drive mechanisms for rotating backups, as I'll explain below.
The heart of my backup strategy is Time Machine. With its automatic, unobtrusive, hourly backups, I entrust Time Machine with the basic backups of my home folder. I don't use it for my entire system, because it would take too long, and because I clone my startup volume regularly. In addition, restoring a startup volume from a Time Machine backup is time-consuming, whereas booting off a clone on an external volume takes seconds.
In Time Machine's preferences, I have excluded a number of items: not only other volumes connected to my Mac, but also certain folders I don't want to back up, which are easy to restore.
Other regular backups
The next step in my backup chain is regular daily backups using Intego Personal Backup. (Disclaimer: I have written documentation for Intego.) I have a backup of my Users folder scheduled for every four hours, and this backup is stored on one of my external hard disks. It's a set-it-and-forget-it system, like Time Machine, where I don't even notice the backups.
In a way, it's a backup to Time Machine, whose hourly backups protect me against immediate data loss, but also provide older files. I only have this backup store four versions, so I'm covered for a day or so.
In come the clones
But those backup methods are nowhere near enough. I use one of my external hard disks for regular clones of my entire startup volume, again using Personal Backup. I run this backup every few days, and I run it manually before any major OS X update. (I don't want this to run automatically, in case something I installed causes problems, and I only discover the problems after my clone has been overwritten with the new software.) This doesn't take long, as the backups are incremental—they only copy new or changed files.
If I have problems with my startup drive, or with Mac OS X, I can instantly boot from that volume and try and solve things. Even though I don't run these clones daily, I have my other backups of user files on another partition on this backup drive, and can access my Time Machine backups at any time. I needed this a few months ago, when, suddenly, my Mac froze, and I couldn't reboot. All the data seemed fine, but the startup volume was no longer "blessed," meaning that Mac OS X didn't see it as a valid system disk. I booted off the clone, copied over my Users folder, then cloned the clone to the original startup volume and rebooted. This too an hour or so, but much less than a full restoration with Time Machine would have taken.
Backups in the cloud
I'm not a big believer in "the cloud" for backups, because of the time it takes to send data to a server. My outgoing bandwidth is only 100Kps, so large backups take hours. Nevertheless, since I have a MobileMe account, I use Apple's Backup to run an incremental backup of my home folder to MobileMe once a week. I've never needed to recover any files from it, but who knows? I may need it some day.
Better safe than sorry
Just in case you thought the above was obsessive enough, there's one more link in my backup chain. While a lot of people suggest off-site backups, it's not really practical for me: I work out of my home, and I can't store a backup, say, at my office. So I have a fireproof safe in my basement, in which I store backup disks.
I have two sets of backup disks, which I rotate every Friday. One is a backup of my media drive, and the other of my startup drive. I use hard drive mechanisms in a disk dock, so the disks are easy to transport up and down the two flights of stairs. Since I have two sets of these disks, one stays in the safe, and the other stays on my desk.
During the week, if I make any major changes to my music collection (rip a lot of CDs, buy anything new), I run a backup of my media disk. I keep that disk in the dock, and turn it on whenever I need to back up my music. Then on Fridays, I switch with the safe disks, and run a new backup over last week's backup, to make sure my music collection is safe from data loss.
One more thing
It's good to have backups; it's better to have multiple backups; but it's even better to be sure of the integrity of your backups. It would be terrible to fetch a backup disk in a time of need and find that it can't be read. So I regularly run DiskWarrior on my backup disks, just to make sure they're in good shape. Also, every six months or so, I erase my backup disks (not all at once, of course), and recopy all my data. This ensures that no files are affected by bad blocks on the disks. Finally, I buy new hard disks every couple of years; I don't trust the long-term reliability of anything mechanical, and newer disks are faster, cheaper and have more capacity.
Is all this enough? Perhaps not. In the competition to see which Macworld contributor is more paranoid about their data, I feel that I'm a few lengths ahead of Dan Frakes. I'm especially concerned about the value of my music collection—not only the music I've bought digitally, but the thousands of CDs I've spent as many hours ripping, tagging and managing.
I'm not in a major earthquake zone, nor in a flood zone, but other tragedies could strike. Nevertheless, I feel adequately protected with my current system. I've lost data many times over the years, because of application or human error, and I've been able to recover it from my backups because of my redundant system.
This story, "My backup plan: Kirk McElhearn" was originally published by Macworld.