Openai/696a9f9f-7fac-800b-8dd9-d6eb037f71e6

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gpt-5-2

User: is RAID a backup

is RAID a backup

Assistant: No.

No.

RAID is not a backup. It is a high-availability and fault-tolerance mechanism, nothing more.

Here is the plain reality:

• What RAID does: Keeps a system online when a disk fails. It protects against single-disk hardware failure depending on the RAID level.
• What RAID does not do: - It does not protect against accidental deletion - It does not protect against file corruption - It does not protect against ransomware - It does not protect against malware - It does not protect against user error - It does not protect against catastrophic failure (controller, PSU, firmware bugs, fire, theft) - It does not preserve historical versions

If you delete a file, RAID deletes it faster across every disk. If ransomware encrypts your data, RAID faithfully mirrors the damage. If the filesystem corrupts itself, RAID preserves the corruption perfectly.

That is why old-school storage admins have always said:

RAID protects uptime. Backups protect data.

What actually counts as a backup

A real backup must meet at least these criteria:

• A separate copy of the data
• Stored on different media or system
• Ideally offline or immutable
• Supports versioning and point-in-time recovery

Examples:

• External drives rotated and disconnected
• Another NAS with snapshot replication
• Cloud backup with object locking
• Tape (still used for a reason)

Correct mental model

• RAID = seatbelt
• Backup = spare life

You want both. One does not replace the other.