The 3-2-1 Backup Strategy

April 7th, 2015

3-2-1 Backup Strategy

In a recent Backblaze survey, 54% of people said they either know someone, or have themselves recently lost data. Most of those surveyed were individuals. If you consider how many businesses have hardware that gets lost or stolen each year as well, the total amount of hardware lost each year is staggering.

Additionally, the study concluded that even with those losses, out of all the companies polled, “two-thirds do not take advantage of even basic security practices, such as encryption, backup and anti-theft technologies.” While Backblaze can’t help with computer encryption or anti-theft technologies (though we can locate a computer), we can help with backup, and that’s what I’m going to focus on today.

What is a 3-2-1 Backup Strategy?

A 3-2-1 strategy means having at least 3 total copies of your data, 2 of which are local but on different mediums (read: devices), and at least 1 copy offsite. We’ll use “kitten.jpg” as an example for this scenario. Kitten.jpg lives on your computer at home, it was a picture that you took of your cat in 2012. That’s one copy of the data. You also have an external hard drive that you use for backing up your computer, if you’re on a Mac, you might be using it as a Time Machine drive (and Backblaze loves Time Machine). As part of its backup process, that external hard drive will back up kitten.jpg. That’s a second copy, on a different device or medium. In addition that external hard drive, you also have an online backup solution. The online backup continuously scans your computer and uploads your data offsite to a datacenter. Kitten.jpg is included in this upload, and that becomes the third copy of your data.

Why 2 onsite and 1 offsite?

Whether you are interested in backing up a Mac or a PC, an onsite backup is a simple way of having quick access to your data should anything happen to your computer. If your laptop or desktop’s hard drive crashes, and you have an up to date external hard drive available, you can quickly get the majority of your data back, or use the external on another computer while yours gets fixed or replaced. If you remember to keep that external hard drive fairly up to date, the exposure for data loss is fairly minimal, as you might only be exposed to losing the files that were on your laptop that had not yet been copied to the external hard drive. Most external hard drives even come with their own software to make sure that they are kept readily updated.

Having an onsite backup is a great start, but having an offsite backup is a key component in having a complete backup strategy. Onsite backups are great if you need to get to them quickly, but unfortunately, having a backup near the device that it’s backing up (for example, having a desktop PC and an external hard drive on the same desk), means that both of those copies are susceptible to data loss. I try not to be too “doom and gloom” on the website but floods, fires, and theft can and do occur. Most often, if the two devices you have as your local copies are close together, they’ll both be affected if the unfortunate should happen. A continuously updated copy of your data that’s not in the same physical location as the other two is paramount in protecting your files.

Is 3-2-1 Perfect?

There is no such thing as a perfect backup system, but the 3-2-1 approach is a great start for the majority of people and businesses. Even the United States Government recommends this approach. In a 2012 paper for US-CERT (United States Computer Emergency Readiness Team), Carnegie Mellon recommended the 3-2-1 method in their publication titled: Data Backup Options.

Backing Up Is Like Investing!

The 3-2-1 plan is a great start in getting your files backed up. If you view your files as your investment capital, you want to diversify them as much as possible to limit your exposure should the unthinkable happen. Liquidity also matters, having a local backup and an offsite backup gives you more options for backup recovery. That’s why Backblaze recommends starting with a 3-2-1 approach. For more information about different backup methods and which might work well for you, please visit the new Backblaze Computer Backup Guide.



Chief Smiles Officer at Backblaze
Yev enjoys speed-walking on the beach. Speed-dating. Speed-writing blog posts. The film Speed. Speedy technology. Speedy Gonzales. And Speedos. But mostly technology. He also runs social for Backblaze.

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  • aviweiss

    Completely agree and have made it more like 2+2; I don’t consider the original a “backup”, but use two separate external drives for Time Machine. I also have two separate online backups (Backblaze and AWS S3) as “anything can happen to any service at any time” (from network outage to bankruptcy).

    Another important aspect of backup is to monitor all medium integrity on a regular basis (SMART and disk until for local and file pulls from online) including pulling random files out of ransoms backup sets.

    Even then, things can go wrong so no such thing as “too much backup”…

  • Greg Zeng

    OneDrive, Google Drive, Samsung, and many other brand-names offer gigabytes of “free” storage. Is there a simple way to collect these many sites into one area, to then auto-synchronize with Backblaze?

  • realist

    Thank you for the post, Yev. I’ve been a computer tech, but I know I’m not an expert in this area. Something I’m concerned about is that if I store data on a cloud service, such as OneDrive or Google Drive, is it susceptible to ransomware? Some ransomware definitely attacks network drives, but I don’t know enough of the details to know if OndDrive files would be attacked.

  • Susan Smith

    I thought using Backblaze would be good insurance. However I recently lost one year of “sent” email that I wanted to retrieve. I used Backblaze and made many attempts to locate that file and never was successful. I communicated with Backblaze staff during this time. I would be given some bit of direction or advice to make another attempt, but it was never successful. I have not attempted to retrieve any other documents at this time, but I am wondering if I would ever be able to locate anything. Although it is comforting to know my data is being backed up, it is useless if I cannot retrieve it.

  • Starman_Andromeda

    Where does the 3-2-1 come in?

    I understand that there are 3 total with 2 on site and 1 off site… but it implies something different– 3 actions, then 2, and finally, 1.

    Of course, 3-2-1 = 0 !

    So really, shouldn’t we represent this as 3 (2-1) or 3 = 2+ 1 or, how about the

    “2 + 1 = 3” backup strategy?

    In any event, it’s important advice and I am forever staggered by business people and students who don’t have backups and lose important documents. (Hint: those aren’t a 2012 kitten picture! :-) )

    • Depends on how you talk about it! It’s 3 2 1, but for the purposes of group the – acts like a space, so 3-2-1. 3 copies, 2 onsite, 1 offsite. 3, 2, 1 :)

      But I do like 3-2-1 = 0 (3 copies – 2 onsite – 1 offsite = 0 files lost? :)

  • Stefan

    I also have more than 3-2-1 backup. My 27″ iMac backs up to Time Machine (of course!) and also to Backblaze. I have a Mac also in my kitchen, and in order to keep all documents/pictures/movies in sync and to be able to reach any document from my iPad/iPhone I also have SugarSync. So every document on my iMac is synced to Sugarsync (another backup) and then to my kitchen Mac, which is also backed up with Time machine (two more backups). So all in all I have my data on 6 places. Even if the house burnt down, I’ll still have all my data in two different places. I feel quite secure.

    • Yup! More is better! 3-2-1 is just a great starting point!

  • Justin Winokur

    This is a good article and a useful strategy. The only thing I would add is that for particularly important stuff, add another level of offsite with something like Dropbox (or OneDrive, Google Drive, etc). There is overlap with Backblaze but they are truly different tools. This is *not* the primary use for those sync tools but good to have. And in my case, putting something in a Dropbox folder means I have a ton of copies because I have a second computer running BackBlaze with a TimeMachine drive. So I have 2 computer copies, 2 Time Machine copies, 2 BackBlaze copies and 1 DropBox copy. Overkill? Yes! But 100% worth it.

    • Absolutely! We can write a whole article (and might) about why syncing/sharing services aren’t a backup strategy, but you are correct, they are another great place to keep your data. 3-2-1 is just a start, the more copies you have the better!

      • Starman_Andromeda

        Of course, that is, if you trust the 3rd party, outside backup company with your *private* data. But, if it’s not worrisome that others have it (say, a school term paper, a backyard garden plan), then saving something to a cloud service, even say your ISP’s backup area (if they still have one) can work well.

        • If you’re worried about 3rd parties, you can always encrypt data on your computer and then back it up to to a 3rd party.

          • NoTroll Zone

            Dropbox is not a backup. If you accidentally delete kitten.jpg, so will Dropbox.

          • Correct, that’s why we recommend having an all-encompassing backup, one that will back up your Dropbox folder as well!

    • Akilla21

      Great point… I think the concept of ensure your data is fully backed up. Helps to avoid the costly charges of data recovery. In my case and Geek Squad a nearly $700 data recovery. But then, the topic of how do you assess cost on memories, important files, and other materials found on your local storage. I wish I’d learned the 3-2-1 strategy a year ago.

  • Loren Gordon

    Does the Backblaze client backup to a local external drive or network share, as well as backup to the Backblaze datacenter? It would be nice to manage both backup sets from one interface…

    • Hi Loren! We currently do not have a local backup interface as most externals come with their own software to do that, but it’s a good suggestion!

      • Loren Gordon

        Yeah, I know Apple has Time Machine (as you highlight in the post) and it’s relatively painless, but I haven’t come across anything as built-in and pain-free on the Windows side. But it seems to me it would be rather nice to have it all in one interface, regardless. Plus, imagine all the restores you could offload to the local backup!

        • Definitely! I believe most Western Digital and Seagate and Hitachi drives typically come with instructions on how to set them up as local backups, but you’re absolutely right, it’s not as elegant as the Time Machine process! Apple really hit it out of the park with that feature.

          • Starman_Andromeda

            Except that it doesn’t create a bootable clone! So, if your laptop is stolen, broken, burns up, etc. there will be pain to go through to resurrect your digital life to where you left off!

          • Very true, we recommend cloning as well in our Backup Guide, you can find it here -> Without a clone you will need to re-download apps/programs, but the data associated with them will be safe, if you have a backup!