How and Why to Double Check Your Backups

When Mac OS X Leopard (10.5) was released, one of the tent-pole features was Time Machine, Apple’s extremely simple, all-encompassing backup solution. With Time Machine, you simply connected your external hard drive, configured a few settings and the utility began backing up your entire computer.

So long as your hard drive is connected, Time Machine continues to make backups on an hourly basis. The hourly backups are consolidated into a single day, every 24 hours and the days consolidated into a week, and so on, as disk space allows.

So your all good, correct? Your data is backed up, you’ve done your job and no matter what happens to your computer, you’ll still have everything in your backup. Well, ideally – yes. In reality, not necessarily.

The entire reason you are backing up your computer is because hard drives fail. A bad drop, a liquid spill, or simply old age, a hard drive will not last forever. So you back up your computer’s hard drive…to another hard drive. Now, if your internal hard drive fails, you have an external hard drive containing a second copy of everything… but as I said, hard drives fail. It’s inevitable. So what to do?

Make triple and quadruple backups? Sure, if you’ve got the time and money, but an easier and more economical solution is simply to check your backups every now and then. Make sure they are running properly, make sure your data is being backed up properly, make sure your the data is not corrupt, make sure you can recover your files properly. A little care and preparation can go a long way.

Suffering a Great Loss

In 2006, I received my first MacBook. The black, Core 2 Duo model. I loved it. In February 2010, the computer overheated, I saw smoke rise up from the under keys and the machine was kaput. It was a devastating day for me.

The silver lining was that my Time Machine drive, sitting on my desk, next to the dead MacBook, was shining like an angel. I purchased a Dell Mini 10v, because I like to tinker, and turned it into a tiny hackintosh. It was a fun little toy and I easily restored my data from the Time Machine drive, my 13,000-song-strong iTunes library fully intact (that was my biggest concern).

Well the Apple gods must not have liked me messing around outside their walled garden, because a few months later, after a hard restart, the little machine simply would not boot. Again, my heart sank. A bit of panic took over me, but again, my Time Machine drive just sat their like a modest white knight. A new computer, fully restored data and once again my life was saved.

Had I not backed up my data, I would have lost my digital life twice in 6 months. With all the seemingly bad luck, I was extremely fortunate that my backup drive remained in tact. I no longer take chances, I can’t experience that heartache (my beloved MacBook!) again. I backup my data and I double and triple-check the external drive containing my data. It’s too important not to.

Checking Your Backup Drive

Verify the Disk

The first step to checking your backup drive is to check for and repair any data corruption. If your drive is full of errors, you’re going to have a tough time accessing any backed up data.

The “Repair Disk” verifies and repairs your disk in one step, if needed.

The “Repair Disk” verifies and repairs your disk in one step, if needed.

Make sure your backup drive is connected to your Mac. Quit Time Machine, or whichever backup utility you use. Open “Disk Utility” and select the backup drive in the sidebar, select the “First Aid” tab in the main window. Click “Verify Disk” in the lower right corner.

The “Verify Disk” operation will check your backup drive for any inconsistencies and errors. If anything is detected, it’s reported in the main window. To repair any errors after the process completes, select “Repair Disk.”

Alternatively, you can bypass “Verify Disk” and simply select the repair option as this will first detect any errors and then automatically repair them.

Disk Utility will repair the detected errors. Not all found errors are cause for extreme alarm, it is normal for data corruption to happen during power outages and forced shutdowns. If Disk Utility is unable to completely repair your backup, you may need to use a more comprehensive disk repair utility such as DiskWarrior.

Verifying the disk only take a few minutes. The progress is shown at the bottom of the Disk Utility window.

Verifying the disk only take a few minutes. The progress is shown at the bottom of the Disk Utility window.

Explore the Data

After you’ve confirmed the integrity of your drive, it’s time to explore your backed up files. Connect your backup drive to your computer. The drive will show up in Finder. Open the “Time Machine” application. The desktop fades away, replaced by a starry background and a seemingly infinite number of Finder windows, fading off into the distance.

Each Finder window represents a date in your Mac’s history, scrollable via the back and forward buttons to the right. Explore the backed up data, ensuring that data has, in-fact, been backed up. If you select your “Desktop” in the Finder window and scroll through time, you should see the changes made to the files living on your desktop.

Your backups appear on your drive just as regular files, sorted by date.

Your backups appear on your drive just as regular files, sorted by date.

If you prefer not to use the Time Machine interface, or do not use Time Machine at all, you can browse the files on the connected backup drive using Finder. Time Machine places the data in time-stamped folders within the “Backups.backupdb” folder. This data is organized just as your current Macintosh HD is.

Restore Your Files

If everything checks out with the backed up data, make sure you can restore the data. It is important to test this process, as a backup is worthless if restoration does not function properly. If you are exploring your data via Time Machine, simply select a previous version of a file or a now-deleted file to restore and click the “Restore” button.

Time Machine will scroll back to the current date, fade away, your desktop will reappear and the restored document will be back in its original location. Open the document to ensure the process properly restored the file.

Exploring your backup and restoring test files may seem like overly simple tests to run, but it is important to know that Mac OS X can properly access and interact with the backup data. Without confirming this on a fairly regular basis, you may be in for a huge surprise (more likely a huge disappointment), the day you actually need to perform these tasks.

Boot the Drive

Of course, Time Machine isn’t the only backup solution. Utilities such as Super Duper! and Carbon Copy Cloner allow you to create fully bootable backups. What does this mean? It means you can connect the backup to your computer, power on the machine and the data on the external hard drive loads instead of the internal.

Imagine your work machine fails and it’s going to be at least a week until Apple’s Geniuses will have it back in your hands. With a bootable backup drive, you can connect the drive to a new computer or your home computer, boot from the backup and like magic, your entire workspace is back in front of you, fully intact.

Bootable backups have the ability to load the entire Mac OS X desktop environment from the backed up image of your Macintosh HD on the external hard drive.

Test your bootable backup by holding down the “Option” key while the system starts up (and the drive is connected). Select the backup from the list of startup disks (“Macintosh HD” will typically be the only other option). Explore your data when the desktop loads to ensure everything is working properly.

Make it a Habit

Checking and double-checking your backups is your only insurance against a failed internal drive. Think of all the family pictures saved in your iPhoto library – chances are you haven’t printed out the majority of them, meaning they only live on your computer.

Think of your iTunes collection, the years and money spent to build up a respectable collection. All your school papers. Your contacts, years of emails in Chances are, many or most aspects of your life pass through your computer at some point. Even the thought of losing all that data is enough to breathe heavy and draw tears.

Backing up your data is the first step in preserving your digital memories and it’s a great first step. The next, possibly more important, step is taking proper care of your backups to preserve their health and extend their life. Make it a habit to test your backups on a weekly and monthly basis!