---
title: "The 3-2-1-1-0 Backup Rule Explained"
description: "The modern 3-2-1-1-0 backup rule for ransomware resilience: three copies, two media, one offsite, one offline, zero recovery errors. Where Firevault fits."
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Recent Breaches 

Breaches 

[2026 PowerSchool 62.4M records ](https://www.bleepingcomputer.com)[2026 DISA Global Solutions 3.3M records ](https://techcrunch.com)[2026 Globe Life 850K records ](https://www.securityweek.com)[2026 Lidl GB Customer contact data ](https://www.theguardian.com/business/2026/jun/11/lidl-gb-third-party-data-breach)[2026 Asahi Group Production systems disrupted ](https://www.reuters.com/technology/cybersecurity/asahi-says-cyberattack-disrupted-operations-japan-2025-09-29/)[2026 Kido International 8K records ](https://www.bbc.co.uk/news/articles/c623d7v0e5xo)[2026 Collins Aerospace (RTX) Check-in and boarding disruptio... ](https://www.bbc.co.uk/news/articles/c789e7l1z7po)[2026 Jaguar Land Rover Production and IT systems disru... ](https://www.bbc.co.uk/news/articles/cx2gx8p3rzeo)[2026 Peter Green Chilled Order and logistics data ](https://www.bbc.co.uk/news/articles/c0k7yy8n3g5o)[2026 Adidas UK Customer contact details ](https://www.bbc.co.uk/news/articles/c78jkev1el2o)[2026 PowerSchool 62.4M records ](https://www.bleepingcomputer.com)[2026 DISA Global Solutions 3.3M records ](https://techcrunch.com)[2026 Globe Life 850K records ](https://www.securityweek.com)[2026 Lidl GB Customer contact data ](https://www.theguardian.com/business/2026/jun/11/lidl-gb-third-party-data-breach)[2026 Asahi Group Production systems disrupted ](https://www.reuters.com/technology/cybersecurity/asahi-says-cyberattack-disrupted-operations-japan-2025-09-29/)[2026 Kido International 8K records ](https://www.bbc.co.uk/news/articles/c623d7v0e5xo)[2026 Collins Aerospace (RTX) Check-in and boarding disruptio... ](https://www.bbc.co.uk/news/articles/c789e7l1z7po)[2026 Jaguar Land Rover Production and IT systems disru... ](https://www.bbc.co.uk/news/articles/cx2gx8p3rzeo)[2026 Peter Green Chilled Order and logistics data ](https://www.bbc.co.uk/news/articles/c0k7yy8n3g5o)[2026 Adidas UK Customer contact details ](https://www.bbc.co.uk/news/articles/c78jkev1el2o)

[View All →](/learn/breaches)

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Why OSS 

# The 3-2-1-1-0 Backup Rule 

Three copies, two media, one offsite, one offline, zero recovery errors. The modern reading of the backup rule, and where a physical air gap sits inside it.

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![Corridor of offline storage racks inside a Firevault bunker](/assets/hero-square-bunker-BC9Flanh.jpg)

R4 

The five numbers 

## What Each Number Actually Requires 

Plain definitions for each digit in the rule, and what a modern ransomware resistant estate needs to satisfy them.

01 

Production plus two backups 

### 3 copies of your data

Keep at least three copies of every important dataset. The live production copy counts as one. Two independent backup copies protect against the failure of any single storage system, and against the ransomware playbook that targets a single backup platform first.

-   Production is copy one
-   Two independent backups
-   No single storage dependency

02 

Diverse failure and attack modes 

### 2 different media

Spread the copies across at least two different storage media. Disk and object storage. Object and tape. Cloud and physically disconnected disk. Different media fail differently and are targeted differently, so a single class of failure or exploit cannot take every copy at once.

-   Diverse storage types
-   Diverse vendors and firmware
-   Diverse attack surfaces

03 

Protection against site loss 

### 1 copy offsite

At least one copy lives away from the primary site, whether that is another data centre, another region or a Firevault Bunker. Fire, flood and localised destructive attacks stop at the site boundary, and the offsite copy remains available to rebuild from.

-   Different site or region
-   Independent power and network
-   Survives physical disaster

04 

The physical air gap Firevault provides 

### 1 copy offline

One copy is offline and out of reach of the production network. This is the modern addition to the classic 3-2-1 rule and the one that ransomware operators cannot defeat remotely. Firevault Offline Secure Storage is designed specifically to be this copy, with Layer 1 disconnection and a tamper evident audit trail.

-   No network path when offline
-   Out of band switching only
-   Tamper evident connection log

05 

Verified restores, not hopeful ones 

### 0 errors on recovery

A backup that has never been restored is not a backup, it is a belief. The zero on the end of the rule requires regular, verified test restores that prove the copies are readable and consistent. A gold copy that cannot be restored on demand is worse than no plan at all.

-   Scheduled test restores
-   Integrity verified end to end
-   Runbooks proven, not written

Read the pillar guide, or continue with the comparison against immutable backup.

[Physical air gap storage for ransomware protection](/learn/physical-air-gap-ransomware-protection) [Air gap vs immutable backup](/learn/air-gap-vs-immutable-backup) [What is Offline Secure Storage](/offline-secure-storage)

Questions 

## The 3-2-1-1-0 Backup Rule, Common Questions

Straight answers on how Offline Secure Storage® behaves in practice.

### What is the 3-2-1-1-0 backup rule?

### How is 3-2-1-1-0 different from the classic 3-2-1 rule?

### Does immutable cloud storage satisfy the offline 1 in 3-2-1-1-0?

### How does Firevault satisfy the offline 1 in the rule?

### How do I prove the zero on recovery to auditors and insurers?

![Mark Fermor](/assets/mark-fermor-C-vy1NeN.jpg)

![David Bailey](/assets/david-bailey-CnLw95Ao.jpg)

![Kenny Phipps](/assets/kenny-phipps-DxIqwaIL.jpg)

Online Now 

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## Add the offline 1 to your backup strategy

Talk to the Firevault team about adding a Layer 1 offline gold copy so your estate satisfies the modern 3-2-1-1-0 rule.

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