---
id: external-drives.what-is-a-raid-enclosure
url: https://storagestudio.us/faq/external-drives/what-is-a-raid-enclosure
category: "External drives"
subcategory: "Choosing a drive"
question: "What is a RAID enclosure, and does it replace a backup?"
alt_questions:
  - "RAID external drive Mac"
  - "Mirrored drives vs backup"
  - "Disk Utility RAID Assistant"
  - "RAID 1 external enclosure for Mac"
  - "is raid a backup"
short_answer: "A RAID enclosure combines several drives: striped for speed and size (one failure loses everything) or mirrored for redundancy. A mirror is not a backup — deletions and damage copy to both drives — so keep a separate backup either way."
tags: ["raid", "mirror", "backup"]
related: ["https://storagestudio.us/faq/external-drives/what-kind-of-external-drive-should-i-use-with-storage-studio", "https://storagestudio.us/faq/external-drives/how-do-i-make-a-backup-of-my-fast-drive", "https://storagestudio.us/faq/external-drives/is-my-external-drive-the-only-copy-of-moved-files"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# What is a RAID enclosure, and does it replace a backup?

A RAID enclosure combines two or more drives into one. **Striped** sets are faster and bigger but lose everything if any one drive fails; **mirrored** sets keep identical copies so one drive can fail without losing data. macOS can also build simple sets with **Disk Utility → File → RAID Assistant**.

A mirror is **not a backup**: deleting a file, a mistake or a damaged file is copied to both drives instantly. You still need a separate backup on another drive or in the cloud.

For most people, one good SSD plus a backup is simpler and safer than RAID — see [what kind of drive to use](https://storagestudio.us/faq/external-drives/what-kind-of-external-drive-should-i-use-with-storage-studio).