Is immutable backup an air gap?

No. Immutable backup is a logical control on a network that remains reachable. An air gap means there is no network path to the data. The two are often marketed as equivalent, but they defeat different classes of attacker and should be treated as complementary layers rather than substitutes.

Which is more resistant to ransomware, immutable or air gap?

A physical air gap is more resistant because it removes the prerequisite that remote ransomware needs, which is a reachable target. Immutable backup remains reachable and depends on identity and configuration holding under attack. In real incidents, attackers have repeatedly weakened immutability from a compromised console before encrypting production.

Do I still need immutable cloud backup if I have a physical air gap?

Yes, in most cases. Immutable cloud backup gives you fast operational recovery from everyday incidents. The air gap gives you the clean gold copy of last resort. Firevault Offline Secure Storage is designed to sit alongside your existing immutable platform, not to replace it.

Can attackers modify data on a physical air gap?

Not remotely. While the storage is offline it has no network path, so no remote command can reach it. During scheduled, identity verified connection windows the write path is controlled and logged on a separate management plane. The remote attacker prerequisite never applies.

How does an air gap satisfy the 3-2-1-1-0 rule that immutable alone does not?

The 3-2-1-1-0 rule adds one offline copy and zero recovery errors to the classic 3-2-1. Immutable cloud storage is still an online copy, so it counts toward the 3 and the offsite 1, but not the offline 1. A physical air gap is designed specifically to be that offline copy.

Why OSS

Air Gap vs
Immutable Backup

Immutable is a logical control on a reachable network. A physical air gap has no network at all. Here is how the two differ, and why the modern answer is both, layered.

Definitions

Two Different Threat Models

Immutable backup and physical air gap defeat different classes of attacker. Start with clean definitions.

A logical control on a reachable network

Immutable backup

Immutable backup means the data cannot be altered or deleted for a defined retention window. Object Lock, WORM and hardened repositories are the common patterns. They live on hardware that remains connected to the network and defended by identity and policy.

Object Lock, WORM, retention policyReachable over the networkEnforced by identity and configuration

No network path at Layer 1

Physical air gap

A physical air gap means the storage hardware has no active network connection when offline. There is no IP address, no listening service and no API to authenticate to. The boundary is physics, not policy, and it holds even when an attacker has domain admin.

No NIC, no IP, no listenerOut of band switching onlyIndependent of identity systems

Where they diverge

What Breaks, What Proves and How They Fit Together

The three questions that decide which layer belongs where in your ransomware resistant architecture.

Where each model fails

What breaks the guarantee

Immutable backup fails when an attacker reaches a privileged cloud account, changes retention, disables versioning or waits out the lock window. A physical air gap fails only when an attacker gains physical presence at the storage, which is outside the scope of remote ransomware.

Immutable: admin, tokens, clock skewAir gap: physical access onlyDifferent threat models entirely

Audit trails and chain of custody

How each proves integrity

Immutable backup relies on the same cloud plane it is defending. Its own audit log lives next to the data. A physical air gap logs every connection and disconnection on a separate management plane, giving investigators, insurers and regulators a stable, tamper evident record.

Immutable: same plane auditAir gap: out of band auditAir gap survives control plane compromise

Layered, not replacement

How they fit together

Most estates keep immutable cloud backup for fast operational recovery and add a physical air gap as the gold copy of last resort. Immutable handles the accident, the deletion and the small scale ransomware. The air gap handles the day the rest of the estate is on fire.

Immutable for hot recoveryAir gap as gold copyTogether they satisfy 3-2-1-1-0

Read the pillar guide, or continue with the backup rule that ties them together.

Physical air gap storage for ransomware protection The 3-2-1-1-0 backup rule What is Offline Secure Storage