Follow the 3-2-1 Backup Rule to Safeguard Your Files

Backup system

Hard drives die. You want to make sure that you have a system in place to back up your data in the event that one of your drives bites the bullet. One way to do so, and to give yourself a few safety nets, is by following the 3-2-1 backup rule.

If I knew where the 3-2-1 backup rule originated, I’d give credit, but it has become such a common backup philosophy that I don’t know who originated it. I first heard about it on one of Leo Laporte’s shows. The 3-2-1 rules goes like this:

1. Keep 3 copies of any important file.

This means keeping your original, plus at least two copies of that original. This builds in redundancy, so that if one of your backups fails, or if a file becomes corrupted, you have it somewhere else.


2. Use 2 different types of media to backup the files.

The idea here is that you don’t want to put all of your eggs in one type of storage basket. So if you back up to a hard drive and also to optical media (like a DVD), you’re protected in the event that one of these fails. In my experience, backing up locally to anything other than a hard drive or network drive is cumbersome, which means that you won’t do it as often as you should. As a result, I bend the rules a bit and count rule #3 as a different type of media.


3. Store 1 copy off site.

If your house burns down, or someone breaks into it and steals all your gear, you’d be out of luck with only local backups. As a result, one of your backups should be offsite. I’ve previously written about CrashPlan as an offsite backup option. CrashPlan offers a free option, if you can back up to your own drive in an offsite location, or to a family member’s computer. If you don’t mind paying for offline backup, the Family Unlimited plan is a great deal, allowing you to back up 10 computers for $119 per year.


Next week I’ll talk about my backup system, which has a few layers of redundancy in it. Do you follow the 3-2-1 backup rule?

Evan Kline

Hello, I'm Evan. I write about tech from my perspective – that of the average 40-something tech geek. You can also find me on Twitter and at my real-life job as a lawyer.    MORE ABOUT ME.


  1. Keep the speed of your internet connection in mind. CrashPlan is a nice solution — great for local backups; but with my connection, its hopeless to back up all important data online. I tried it …

    My documents are stored in my wuala folder (an encrypted dropbox alternative).

  2. I prefer using secondary drive to store all my data rather than storing it on my main drive. The main drive can fail at any time, as it used most of the time by the system. And in case if it fails then the secondary drive remains safe.

    Good article with good tips. Thanks you.

    • I’ve actually never had a primary drive fail (owned computers for 15 years, often more than 1), but I have had two external backup drives fail during the same span – and I do periodic manual updates, so the external drive is almost never running. At this point, I’m just chalking it up to random luck.

      • Actually, I guess I have had one primary drive fail. It was a work laptop and it died right before I was going to take a couple weeks off for the birth of my son. My goal was to keep on top of email somewhat during that time, but that didn’t work so well :)

      • You do know that you just jinxed yourself, right? I foresee a future of failed drives for you in the coming weeks.

        I’m hesitant to say that I, too, have never had a drive fail. So that means a few will fail this week.

    • Just make sure the secondary drive isn’t your only copy. It stands as good a chance of failing as your main drive.

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