Free tool
3-2-1 Backup Rule Checklist
Three questions to check whether your data actually survives a bad day.
At risk — a single failure could mean permanent data loss.
• Add another backup copy — a second external drive or a cloud account both count.
• Diversify media types — if all your copies are the same kind of drive, they can fail the same way.
• Add an off-site copy — a cloud account is the easiest way to cover this if a fire or theft takes out your local copies.
The 3-2-1 rule is the closest thing the backup world has to a universal standard: keep at least 3 copies of your data, on at least 2 different types of media, with at least 1 copy off-site. It's not a calculator — it's a checklist, and most data loss stories trace back to skipping exactly one of these three things.
Answer honestly. “I have it on my laptop and an external drive” sounds like two copies, but if both are sitting on the same desk, a fire, flood or theft takes out both at once — that's the gap this checklist is built to catch.
How to use it
- 01Answer the three questions honestly, based on your actual current setup.
- 02Read the verdict — full coverage, partial, or at risk.
- 03Follow the advice for whichever piece is missing.
Frequently asked questions
Does cloud storage count as one of the three copies?
Yes — a cloud account counts as both a different media type and an off-site copy in one step, which is exactly why it's such an efficient way to close gaps in this checklist. It should not, however, be your only copy.
What counts as a different “media type”?
Different physical technology, not just a different device. Two external hard drives are the same media type. A local drive plus a cloud account, or a local drive plus a different drive technology (like a NAS or optical media), counts as two.
I only have one copy. Where do I even start?
Start with an off-site cloud copy — it closes two gaps in the checklist at once (media type and off-site) with the least effort. Purgify won't create backups for you, but it does make sure the cloud accounts you already use aren't quietly full of duplicates when you need the space for exactly this.
Related tools
This is what Purgify automates.
Connect your cloud accounts and Purgify finds duplicates and reclaimable space like this — across all of them, on a schedule.
Want early access? Write to us at [email protected]