---
title: RAID is not a backup — and the difference has ended businesses
description: RAID protects against a drive failing and nothing else. What a real 3-2-1 backup looks like, and why an untested restore is not a backup at all.
source: https://samuelmarndi.com/blog/raid-is-not-a-backup/
site: https://samuelmarndi.com
author: Samuel Marndi
contact: +91 82803 20550 · samuelmarandi6@gmail.com
updated: 2026-08-22
---


# RAID is not a backup — and the difference has ended businesses

*Guide · Updated 2026-05-18 · By Samuel Marndi*

## Short answer

**RAID is not a backup. It protects against a physical drive failing, and nothing else.** Accidental deletion, ransomware encryption, fire, theft and silent file corruption all defeat RAID completely — and in the ransomware case, RAID faithfully replicates the damage across every disk in the array.

You need both: RAID so a dead disk is an inconvenience rather than an outage, and a real 3-2-1 backup — three copies, two media types, one offsite — so a bad decision or a bad actor is recoverable.

## What each one actually protects against

| Threat | RAID | Backup |
| --- | --- | --- |
| Single drive failure | Protects | Recovers, more slowly |
| Accidental deletion | No help | Protects |
| Ransomware | Replicates the damage | Protects, if a copy is offline or immutable |
| Fire, flood, theft | No help | Protects, if a copy is offsite |
| Silent corruption | Sometimes, with checksumming filesystems | Protects, with versioned history |
| Someone deleting the array | No help | Protects |

## What a real backup looks like

- **Three copies** of anything you cannot afford to lose
- **Two different media or systems**, so one failure mode cannot take both
- **One copy offsite**, because fire and theft do not respect a server room
- **At least one copy offline or immutable**, because ransomware attacks the backups first
- **Versioned history**, so a file corrupted three weeks ago is still recoverable
- **A documented restore test you have watched** — this is the only part that constitutes evidence

## The test that separates real from theatrical

Almost every business I audit has backups running. A much smaller number have ever restored one. Until you have watched your own data come back, you have a scheduled task and a hope.

Run a restore test at least twice a year, with the procedure written for someone doing it under pressure at 2am. If the only person who knows how is on holiday when it matters, you did not have a backup — you had a person.

## Related questions

### Is a NAS enough on its own?

No. A NAS with RAID is a good primary copy, but it is one device in one building. It needs an offsite or cloud copy behind it, and ideally an immutable one.

### Is cloud storage a backup?

Sync is not backup. If a file is deleted or encrypted locally, a syncing service happily propagates that. Use versioning and retention settings, or a real backup product pointed at cloud storage.

### How often should we test restores?

Twice a year at minimum, and after any significant change to the systems or the backup configuration.

## Related service

- [Servers & storage](https://samuelmarndi.com/services/servers-storage/) — Server specs, NAS, RAID, virtualisation, backups


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*Published by [Samuel Marndi](https://samuelmarndi.com), independent IT consultant, Bengaluru, India.
Source page: https://samuelmarndi.com/blog/raid-is-not-a-backup/
Enquiries: +91 82803 20550 (phone and WhatsApp) · samuelmarandi6@gmail.com · Mon–Sat, 9am–7pm IST
Quotes are written and itemised, issued within 24 hours.*