Last week, I wrote an article about the importance of having a backup of your backup. The main scope of that article was to showcase Time Machine’s “archive” feature. I received several great responses from readers who create their secondary backups in a variety of ways and I realized there seems to be a real need to explore the many ways we choose to backup. Since this is such a loaded topic I’ll be breaking it out into a few articles ranging from basic to complex. This week, we’ll be focusing on bootable versus non-bootable backups.
One concept that I quickly want to elaborate on is the idea of having a “backup of a backup.” The point of that phrase is that it’s always a good idea to have two backups of your data. It appears that was taken quite literally so I want to explain that I don’t mean to imply that one should always have a clone of their primary backup, rather I recommend that one has two copies of their data. To some, they may just want to do a Time Machine archive, others feel more secure having two different types of backups, some like a combination of all of the above.
As someone who sees a lot of data loss, I admit that I’m a little paranoid at times. My primary backup is my Time Machine backup on my Time Capsule. As I mentioned last week, I’m now also doing archives of my Time Capsule on an external drive that I physically put in a separate location. What I didn’t mention is that I always have a bootable backup as well. I’ll admit I only make a new bootable backup once every few months so it’s not my most current backup. However, I consider a bootable backup to be my most functional backup and for those of you who only have one computer, it can be an important thing to have lying around.
A bootable backup is literally a clone of a computer, complete with system files that allow a computer to boot to the external drive, just like we usually boot to the internal drive. While this is great if you lose data, its functionality goes far beyond data retrieval. Let’s say your computer won’t boot up entirely—maybe it’s hanging at the Apple logo or at a blue screen—you can plug in you external bootable backup, hold down the option key on boot and select your external drive to boot to.
Congratulations—you just did your first troubleshooting step on your own machine. If you successfully booted to the external hard drive, that implies that something is up with your internal hard drive: corrupt software, failing hard drive, failing SATA bus, etc. (you’ll find there are rarely absolutes in computer repair). If you were unable to boot to the external drive, it could imply there’s a bigger issue with the computer or it’s possible that whatever software corruption exists on your internal drive is also present on your external clone.
Let’s assume you were able to boot to your external drive. The next troubleshooting step here is to open Disk Utility (/Applications/Utilities/Disk Utility), select your internal drive and try to repair the disk. If it finds errors and repairs them you might be all set. If it finds errors and cannot repair them, you know you’re at least looking at software corruption, though software corruption can be a symptom of a failing hard drive or bad RAM; again, no absolutes.
From here, you could run a surface scan or integrity check with diagnostic software like Drive Genius or you can jump right to an Archive and Install of the operating system using your system disks. Personally, I run Drive Genius first to check for hardware errors before tackling the software, but many home users don’t have tools like Drive Genius so Apple often recommends trying the Archive and Install as a next step.
Let’s say at this point that you decide to take your computer in to your local Apple Authorized Service Provider for repair. What are you going to do in the meantime while your computer is in the shop? Well, if you have another Mac at home or if your shop is awesome like Small Dog and offers loaners during repair, you can boot to your bootable backup and continue on with your work or play as if nothing had happened (depending on how current your backup is). This is a great way to avoid downtime and it’s even more convenient than Time Machine in the sense that if you had a Time Machine backup and brought a loaner computer home, you’d have to wait for Time Machine to restore on your loaner (which can add hours to your downtime).
Once you get your computer back from repair, if you’re missing data it’s just as easy to restore from a bootable backup as it is to restore from a Time Machine backup. Simply plug in your external drive and in the Mac OS X Setup Assistant when it asks if you’d like to transfer data, choose that you’d like to transfer from another Mac and you’ll be all set!
There are several ways to make a bootable backup. I recommend one of two programs, SuperDuper! or Carbon Copy Cloner. Both are great, easy-to-use apps that automate the cloning process and make it easy to create bootable clones. They also both offer incremental backup options so you don’t have to do a full clone every time you want to update your backups.
Now, there is some fine print. If you create a bootable backup from a PowerPC machine you cannot boot to it using an Intel-based machine and vice versa. Both CCC and SuperDuper! will also remind you that to make a bootable backup from a PowerPC machine, the drive must be formatted in APM and for an Intel machine it must be formatted in GUID; both should be Mac OS Extended (Journaled). All formatting can be done using Disk Utility. It’s also important to note that most PowerPC machines can only boot via FireWire so if you have a USB-only external hard drive, that would not be a good candidate for your backup unless you’re on an Intel-based Mac.
For those with the burning question of, “So is a bootable backup better than Time Machine?” Well, that’s entirely up to your own point of view. Some will vehemently say “yes” while others, like myself, are more neutral about it. I use both and feel they have different purposes and offer different levels of convenience. As you’ll see in my subsequent articles, there is no singular end-all-be-all backup solution. The best idea is to learn about the options and choose for yourself what you’re comfortable with. What even more ideas? Check out my article next week on RAIDs!