There are two main types of "air gaps

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But there is good news: more and more vendors are applying immutability to more than just object storage.

“This goes back to the evolution from hardware-based WORM to software-based technology,” explains Paul Special, chief product officer at object storage maker Scality. “Ultimately, all storage systems sit on top of underlying block storage systems, so immutability must be provided at the software layer that manages the storage.”

How does an "air gap" work?
Another way to improve data security is to take a separate copy of your backups offline. This "air-gapped" copy is often stored in a remote location.


A physical air gap disconnects the backup from the network after it is written, and then reconnects the network;
A logical air gap sends backups to a physically separate location. However, such backups are not completely disconnected from the network. Backup software does the heavy lifting of preventing backups from being overwritten or deleted.
An offshoot of the air-isolation method is finland mobile database storage—an autonomous location physically and logically isolated from the production environment.

Despite the effectiveness of air gapping, relatively few organizations take advantage of the technology. Research by Enterprise Strategy Group found that only 30% of organizations have deployed an air gap separating production and backup networks.

Immutability, air gap, or both?
So, how should you go about incorporating at least one of these data protection methods into your technology stack and processes? According to Christophe Bertrand, practice director at Enterprise Strategy Group, the decision depends on both the architecture and the business.

“It depends on your goal. If you’re talking about hardening or enhancing your backup infrastructure, you want backups that are stored on some type of immutable media,” he says. “If you need archives for compliance purposes or you need to demonstrate that it’s tamper-proof, then the question of what tier to choose becomes different. If you need to keep data for 30 years, you don’t want to put it on expensive disks.”

In addition to determining the best architectural option, there are, of course, economic considerations to consider, says Oscar Arean, CTO of Databarracks. “In some cases, one of these options may initially seem like a great idea, but it may actually increase your backup costs,” he explains. “You need to weigh the additional cost against the potential risk and figure out what makes sense for your particular use case.”