Ignore The Rule Of 321 At Your Peril

Ignore The Rule Of 321 At Your Peril

Recently on the DocumentSnap newsletter I wrote about an important concept in protecting your paperless documents: The Rule of 321.

The general concept is that you want your data in as many places as possible:

  1. Have at least 3 copies of your data – In other words, have your original PDFs (1 copy) and 2 backups (2 more copies to make 3).
  2. Keep these backups on 2 different media – Don’t have your originals and your backups on the same drive. Don’t just rely on CD or tape backups. What happens if you no longer have a CD or tape drive? If you’re old like me, you’ll remember ZIP drives.
  3. Store 1 backup offsite – Whatever happens to your computer could happen to your backup drive too. Keep at least one copy in a different location.

I had a lot of responses to that newsletter, but here is a situation I’ve certainly never heard of from a DocumentSnap reader. Here’s what they had to say:

Your article gave me a chuckle. Here's why.

I'm very careful about backing up. I assume that one day the burglars will come and take my IT equipment or the house will burn down or encryption malware will – despite my extensive anti-malware precautions – render my data inaccessible. Several years ago a nearby lightning strike generated a voltage spike/current surge that destroyed my PC (the IT repair shop found one of the cards covered with Lichtenberg discharge figures and the HDD controller no longer worked).


  • My priceless family photos and videos and music are kept on a network server with RAID redundancy.
  • Those files and all the other data on my PC and other office equipment are backed up weekly to an external hard drive (HDD) which is kept in the vault of a local bank conveniently situated 5 minutes by bike from my home.
  • A second HDD which is kept at home is used for in-between backups during the week, e.g. following creation of a large number of files.
  • I unplug everything if there is a thunderstorm in the vicinity or forecast, e.g. during the night.
  • A log of the backups is kept on a cloud server so that, when disaster strikes and I have to buy new equipment and restore images, I'll know what is where.
  • I regularly check my external HDDs with the free Seagate disk checker. A Seatools check threw up an unacceptable failure rate of one of my external HDDS a few months ago and the HDD was scrapped.

100% sure. Belt-and-braces. Right ? Wrong. Our village is halfway up a gently sloping hillside in a river valley. The bank with its vault is around 250 metres below us. A few years ago there was a catastrophic storm. The downhill rush of water washed away the roads connecting the village to the outside world and part of that water flowed into the bank vault. When I went to collect my HDD for the weekly backup they were still pumping out the vault. The high water line around the vault stopped just below my strongbox so I was able to take out a still-dry and working HDD but a couple of inches more and it would have been soaked.

So all was fine because I still had my intact data back home and the backup HDD had just avoided a soaking but this was a lesson. Even if the backup data is offsite – in a bank vault, for Heavens' sakes – that off site may be insecure.

This is such a great example of the need to keep multiple backups in different locations. Now, it is very possible that where you live may never have bank vaults filling up with water, but it is very possible that something is going to happen to one or more of your devices.

Ignore the rule of 321 at your peril!

Do you have any similar stories of backup intentions gone awry? Leave a comment and let us know.

About the Author

Brooks Duncan helps individuals and small businesses go paperless. He's been an accountant, a software developer, a manager in a very large corporation, and has run DocumentSnap since 2008. You can find Brooks on Twitter at @documentsnap or @brooksduncan. Thanks for stopping by.

Leave a Reply 10 comments

Old luddite - January 20, 2018 Reply

With all the nation’s natural disasters whirling around over the past year, from hurricanes to blizzards, fires, then floods, the extent to which the real world can wreak havoc on the best plans is more revealed than ever. Redundancy is vital, but when major events hit an area, everything within that area is at risk; even secure bank vaults do not guarantee protection, and unless distance is imposed between source and a backup, both are at risk from the same event. This is certainly one argument favoring a Cloud-based backup for one choice; if one needs to use some extra security like encryption for peace of mind with this choice, that immediately entails redundant backups of the means by which to “unlock” the security as well as merely accessing the materials. Password keepers are great, if you don’t lose them, and so the entire realm of data protection keeps expanding and expanding . . .

Thierry - September 5, 2017 Reply

I have some question to the crazy “backup people” like me:
What is your solution if you are mainly using a laptop with limited space? (say 256GB of SSD, because the 1TB is soo much expensive) but you are still having about 500GB of family pictures and movies.

I am planning to move away of the desktop + laptop. (because I do all on the laptop, but I can keep all data on it)

Having a separate external drive is not so convenient.
Or a NAS, but it’s not so fast to access data.
I also thought to use iCloud drive, which is clever enough to only keep the current “used” files on the laptop, and the rest stays in the cloud until I need.

Please, I would love to hear some ideas of your current set up.

thanks again for this great web site, blog and paperless method + documents.
You made me move to this new world, 2 years ago with the purchase of my S1300i.
I’m still scanning my documents every week and it’s a big change in my family life.

    Steven Buehler - September 5, 2017 Reply

    Thierry, I use the 1 TB OneDrive that’s included with my Office 365 to store my stuff offline; if you’re short on local space you can sync just the folders you want to have a local copy of rather than the entire OneDrive. The Fall Creators Update for Windows 10 is supposed to bring back the “link” model where you can sync to your local machine as links, and the files will automatically download/update/upload as needed so you don’t need to have a local copy. It was a feature present in Windows 8.0 but taken out in 8.1.

    I’ve also been very happy with Seagate’s Personal Cloud drive (I have the 4 TB model) and I scan to it from my HP OfficeJet all-in-one over the network. I can also securely access the drive remotely via Seagate apps without having to mess with my router.

    If you’re a Google fan you can invest in a large Google Drive account and simply use a Chromebook with Google Docs, which I also do a lot of, but it relies on you being almost constantly connected since the internal storage is usually limited (around 16GB or so). Google is slowly pushing updates to Chromebook devices to support Android apps natively as well.

Stefanie - May 28, 2017 Reply

Hello, just found your blog and think it is really important to have a proper backup strategy. My backup plan has several locations within my and outside home. Backups are fully automated and will backup my mobile devices and all other computers to my own cloud (NAS). Afterwards, there will be a Raid-Backup on a different location outside home (another NAS is located at my sister’s house). Further to this, there is a third backup on a hard drive too. There will be several timings for the backup to be processed and a “Son-Father-Grandfather” strategy is in place too.

If something burns or gets under water, I just have to connect to my NAS at my sister’s and be again up and running with the latest files.

Have all a good Sunday!

http://www.steffiscloud.de (also in English available 🙂 )

IB - April 15, 2017 Reply

I scan every document and put it in OneNote. It gets then synced across my Mac Mini, MacBook, office Dell, iPad and iPhone as well as to OneNote’s servers. It’s very simple, no making backups, no biking to the bank etc. If my house burns down there is a backup at Microsoft, one in my office and most likely my iPhone is in my pocket. If Microsofts servers fail I will have my own devices.

My precious photos sync all to my devices and to iCloud where I have 200Gb (cheaper than renting a safe)

Do I miss something? Anyone?

Oh, and I don’t care about that maybe the NSA can read my files. I have nothing to hide and I’m located in Europe

    Thierry - September 5, 2017 Reply

    Hi IB,
    I’m replying late, I don’t know if you would read this message…

    If all your data are synched, you cannot call it a backup plan, in my opinion.

    For example, your laptop gets corrupted and all your pictures are encrypted by a malware. Before your notice it, it’s uploaded to the cloud, and pushed down to your home desktop, office desktop and mobiles.
    You lost everything on all your devices.

    That’s why a “disconnected” backup is also important. (or even 2 external backups 🙂 )

Tara D - April 13, 2017 Reply

Sigh…I just wished I lived in a village halfway up a gently sloping hillside in a river valley. 🙂

Jim Sewell - April 13, 2017 Reply

Makes me consider putting backup hard drives in zippered watertight baggies! Who would have thought about a vault being flooded?

John Marra - April 4, 2017 Reply

My data, docs, pictures, music, etc are stored in 3 places. The workstation, my local Synology NAS, and in the cloud via CrashPlan.

Steven Buehler - March 15, 2017 Reply

On my Windows machine, my default document, video, and picture directories sync with OneDrive with nearly all my scans in OneNote both in PDF and viewable image form. Also, most if not all network-attached storage has some way to back itself up online (Seagate Personal Cloud, which I have, is able to back itself up to Amazon S3, Baidu (pcs), Box, Dropbox, Google Drive, Strato HiDrive, Yandex.Disk, OneDrive, or any combination thereof, as often as hourly).

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