ismagilov/iStock/Getty Images PlusZDNET’s key takeaways
- The 3-2-1 backup rule is what data security experts recommend.
- It’s easy to follow, using popular cloud services and free backup software.
- Backups work best when they’re automatic, but be sure to verify them.
One of the best-loved movies ever made almost disappeared before it was released, because an engineer working on a Unix workstation accidentally deleted the contents of an entire server. It is the ultimate cautionary backup tale.
Pixar Studios had a backup of Toy Story 2, but no one had ever tested the backup, and of course Murphy’s Law says … well, you can probably guess the rest. The backup was corrupted, and the studio was about to suffer a catastrophic $100 million loss. (It was 1998, and $100 million was a lot of money back then.)
Also: Why you need a data backup plan for your Mac or PC – before disaster strikes
The studio eventually recovered everything through a fortunate chain of events — an employee had been working remotely (in 1998!) and had a copy on their workstation. The story would probably make a good movie all on its own. There’s even a fun plot twist.
As it turns out, Pixar’s engineers had stumbled accidentally onto a fundamental principle of effective backups, although it would be a few more years until photographer Peter Krogh gave it a name: the 3-2-1 rule. If you search for that phrase, you’ll discover that it’s recommended by nearly every data recovery expert in the world. It’s not complicated to set up and it’s not expensive.
I bring this all up because even though your collection of digital files is probably not worth $100 million, I guarantee there are some files there that you consider extremely valuable, like scanned copies of tax returns or pages of research notes or near-final drafts of a dissertation. Some are irreplaceable, and some are literally priceless, like pictures and videos of your kids and pets.
In this post, I explain how this backup strategy works and how I’ve made it work for my important data files.
What is the 3-2-1 backup rule?
Following the 3-2-1 rule helps you protect your data from all reasonably foreseeable threats. Here’s how it works.
- Keep at least three copies of every data file. That includes the original file plus at least two backup copies.
- Use at least two different types of storage media. Your primary copy might be on an internal storage device on your PC or Mac or, if it’s an archived file that you don’t need for current work, on an external drive. Your backups might be in the cloud, on a network-attached storage device, or on a separate external drive.
- Keep at least one copy in a separate location.
- Bonus points if at least one copy is also immutable — that is, it can’t be modified or deleted. (OneDrive cloud backup offers this as part of their ransomware protection feature.)
Why does all that matter? Let’s break it down:
3 – Having (at least) three copies reduces the risk of data loss from a single event. If a ransomware attack encrypts your local files and the backup copies on your external drive, you’ll need that third backup.
2 – Using multiple media types protects you from a hardware-related single point of failure. Keeping backups on two external drives from the same manufacturer might be a problem, for example, if a firmware bug causes data corruption on both drives. If the second backup is on a NAS or in a cloud storage service like OneDrive or Dropbox, you’re much better off.
1 – You need an offsite copy to protect against actual disasters, like a fire, flood, or tornado. Backing up the files from your work PC to an external drive offers great protection if the PC drive crashes. But if your office is wiped out by a natural disaster, you’ll be glad you had the copy you stored in the cloud or on an external drive that you brought home for safekeeping.
My 3-2-1 setup
Over the years, I’ve accumulated a lot of data files. Some are from work, some are personal. I have large libraries of photos that date back several decades, as well as a large collection of digital media files that aren’t available on any streaming service — like live recordings of concerts and copies of rare albums. Here’s how I have them organized.
My primary copies are in the cloud: personal files are in OneDrive, while work files are in OneDrive for Business. The files I am currently working with are synced to the PCs I use every day. When I create a new file, it’s saved on my PC and synced to the cloud immediately.
In the corner of my office is a five-year-old Dell Precision laptop running Windows 11, with two USB 3.2 Gen 2 external drives attached — one with 4 TB of storage, and one with 8 TB. (I am very glad I bought those external drives a couple of years ago, before prices went insane.)
Also: I built my own secure network in the cloud to access my home PCs remotely – for free
That PC hosts a handful of virtual machines that I use for testing purposes, but its primary role is to be a file backup server. It’s connected to both my personal OneDrive account and my OneDrive for Business account, and both of those accounts are set to sync their full contents to one of the local drives.
That system is also running a copy of a dedicated backup program, MSP360 Backup (formerly known as CloudBerry Backup). A background agent on that PC periodically backs up an image of the system drive to one of the local external drives; a separate backup plan copies my cloud storage files to a B2 Cloud Storage Bucket at Backblaze once a week.
And just for good measure, once a month, I back up the entire contents of each OneDrive store to an external drive.
That’s at least three copies of every file, on multiple storage media, with two separate offsite repositories.
How much does it all cost? The cloud storage (6 TB personal, 1 TB for business) comes with my Microsoft 365 subscription. In total, those are about $25 a month. The MSP360 Backup software has a free edition as well as a Pro edition that costs $30 a year. The free edition would work for me, but I purchased a lifetime license for the Pro edition long ago, so I don’t have any ongoing costs. My Backblaze bill is under $5 a month.
The best part is that everything runs automatically. OneDrive files sync automatically with Windows, and if there are sync problems I can see an error message immediately. I get email notifications after each MSP360 backup completes; if there’s an error, the details are in the email.
How to build your own backup strategy
Your requirements and your preferences (and your hardware!) are almost certainly different from mine, but you can follow the same general principles. Feel free to substitute Dropbox or Proton Drive or Google Drive, if that’s what you prefer for a cloud provider. If you’re not willing to use the cloud, the backup job becomes much tougher.
As for backup software, both Windows and Mac have built-in file backup tools (File History and Time Machine), but the commercial tools are much more versatile. I’m also evaluating Macrium Reflect X and have been impressed with its speed and performance. Macrium used to have a free product, but that’s no longer available. I paid a discounted price for a 4-computer license on a Black Friday special; the full price for a single PC is $100 a year or $200 for 4 PCs.
The most important advice I can offer is to inventory the files that matter to you and make sure they’re being backed up. My iPhone photos, for example, are uploaded to OneDrive automatically; you might use iCloud Photos or Google Photos instead. If your work files are in the cloud, make sure everything is being stored in a location that’s being synchronized. OneDrive doesn’t automatically sync your Downloads folder, for example.
Your backup routine should be automatic. If you have to remember to run a task manually, you’re going to forget at some point, and you will end up losing data.
And make sure you know how to verify your backups and how to restore your files. What I like about the backup software I’ve chosen is that it performs the verification automatically. But I also occasionally go in and manually check to see that I can restore a file or folder, just to reassure myself that the backups are working and that I know how to use the restore capabilities.
If you have a favorite backup strategy I haven’t mentioned here, please drop a note in the comments or send me a note using my contact form.
