Backup basics

The 3-2-1 backup rule: what it means and a plan for your home

Three copies, on two kinds of storage, with one copy somewhere else. Where the rule comes from, why one copy should be offline, and how to set it up at home with a drive and a cloud account.

Updated 5 October 2026 · 5 min read

Most people discover they had no backup on the day they need one: a phone falls in the water, a laptop is stolen, a drive stops working. The 3-2-1 rule is a short way to avoid that day. It isn't a product you buy, it's a routine you can set up in an afternoon and keep with a reminder in your calendar.

What the 3-2-1 rule says

The name comes from photographer Peter Krogh, who coined the term “3-2-1 rule” while writing the first edition of The DAM Book, a guide to managing digital photo collections. As backup specialist W. Curtis Preston put it when interviewing him, Krogh didn't invent the idea of several copies and an offsite backup, he distilled it into something easy to remember. Krogh's own text on dpBestflow, a project of the American Society of Media Photographers, recommends:

• 3 copies of any important file: a primary and two backups;
• 2 different media types, “to protect against different types of hazards” (his example: hard drive and optical media);
• 1 copy offsite, “or at least offline”.

Public bodies use the same rule. The paper “Data Backup Options”, written by Carnegie Mellon University for US-CERT in 2012, says to keep 3 copies of any important file (1 primary and 2 backups), on 2 different media types, with 1 copy stored offsite, “outside your home or business facility”. For home users it suggests keeping the primary files on the computer's hard drive, with at least two backup copies. The UK's National Cyber Security Centre (NCSC) calls 3-2-1 the most common method for creating resilient backups: at least 3 copies, on 2 devices, and 1 offsite.

Why one copy should be offline

The NCSC adds what it calls the offline rule: keep at least one backup offline at any given time, so that “an incident cannot affect all of your backups simultaneously”, and never have all your backups connected at the same time. Think of ransomware: malware that can reach a drive can also encrypt or delete what's on it, and a backup drive that is always plugged in is within reach. The NCSC's advice for home users says the same thing in plain words: when removable media isn't in use, disconnect it.

Cloud sync is not a backup

Many people believe their photos are backed up because they are “in the cloud”. Often they are synced, which is a different thing. Sync keeps two places identical, mistakes included. Apple, for example, explains that with iCloud Photos, photos you delete are deleted on all your devices. The rclone documentation says its sync command updates the destination to match the source, “including deleting files if necessary”, while rclone copy doesn't delete files from the destination.

A backup is a copy that doesn't follow your deletions straight away: a drive you update and then unplug, a copy that never deletes, or a service with a trash and version history that lets you go back.

A 3-2-1 plan for a household

1. List what matters. Family photos and videos, scanned documents (IDs, contracts, medical and tax papers), work files, anything you couldn't download again. Next to each item, write where it lives today: which phone, which computer, which online account. If something exists only in an online account, that account is its only copy.
2. Copy 1 is the original, on your computer or phone. Gather what's scattered into a few clear folders on one computer, so the next steps have one place to copy from. Move photos from the phone to the computer regularly.
3. Copy 2: an external drive, on a schedule. Choose a fixed day, for example the first Sunday of every month, and copy those folders to an external hard drive or SSD. That's your second type of media.
4. Copy 3: offsite, in the cloud. Upload the same folders to a cloud storage service. This covers fire, theft or flooding at home, which could take the computer and the drive together. A second drive kept at a relative's home also counts as offsite.
5. Keep one copy offline. As soon as the copy in step 3 is finished, unplug the drive and put it away: that's your offline copy. If you have two drives, alternate them, so one is always disconnected even while you update the other.
6. Test a restore every few months. Pick a few files at random, copy or download them back into a different folder, and open them. Check a photo, a PDF and a large video. If something doesn't open, you've found the problem while the originals still exist.

Where LifetimeCloud fits

LifetimeCloud can be copy 3, the offsite one. A few details matter when you use it as a backup:

• When you upload from the website, the content of your files is encrypted on your device before it leaves, with AES-256-GCM.
• Files deleted on the website go to the trash for 30 days. When a file is replaced, the website keeps its earlier versions for 1 year (“Version history”).
• Uploads through WebDAV (rclone, Cyberduck, a network drive, backup apps that use WebDAV) are stored as they arrive: protected in transit by HTTPS, but not end-to-end encrypted. For encrypted automatic backups, wrap the WebDAV remote in an rclone “crypt” remote, as explained in our rclone and WebDAV guide, or upload from the website. Through WebDAV, deleting is permanent (no trash) and version history is 30 days, last 3 versions, so prefer rclone copy to rclone sync.
• Save your recovery key: without your password and without that key, nobody can open the encrypted files, us included. See why the recovery key matters.
• Our own Terms say it too: don't use LifetimeCloud as your only copy. It's one of the three.

The free plan gives you 1 GB (up to 50 files, 50 MB each), with no card: enough to start with your most important papers, as described in how to protect important documents. Paid plans (1 TB and 2 TB) are a one-time payment with no subscription; current prices are on the plans page. An offsite copy only helps while it exists, so before choosing any service read what happens to your files if you stop paying.