Immutable Backups for SMBs: What They Are and When You Actually Need Them

For years, backup strategies for small and midsized businesses (SMBs) followed a familiar pattern: copy the data, store it somewhere safe, and hope you never need to use it. But with the rise of targeted ransomware, insider threats, and increasingly complex regulatory requirements, many SMBs and MSPs have had to reconsider what “safe” truly means.

Enter immutable backups, one of the most effective modern protections against data tampering and malicious encryption. While the concept has quickly become a buzzword in the enterprise space, most SMBs still aren’t entirely sure what it means or whether they need it. This article is designed as a practical, plain-language guide that MSPs can share with their clients to help them understand the real value of immutability, where it fits, and where it doesn’t.

What Is an Immutable Backup? (The Simple Version)

An immutable backup is a copy of data that cannot be changed, deleted, or overwritten for a set period of time. Once created, the backup stays exactly as it is until its retention period expires.

In practice, immutability usually comes from one of three places:

• A storage system that enforces a write-once-read-many (WORM) policy
• An object storage service that supports locked retention (like S3 Object Lock)
• A backup platform that prevents modification of a backup job’s historical versions

For most SMBs, this doesn’t require new hardware or a major infrastructure change. The immutability layer is often built into the cloud storage or backup software that’s already in use. The key is whether the system can guarantee that no one — not an administrator, not ransomware, and not even an attacker with valid credentials — can alter the protected copy. This "locked copy" is what gives immutability its power.

Why Immutability Matters Now More Than Ever

Not long ago, ransomware mainly targeted production systems. Today, threat actors deliberately go after backup files as well. If they can encrypt or delete those backups quietly before launching the main attack, the victim loses its safety net. That’s why so many MSPs now include immutability in conjunction with their backup strategy to help mitigate the risks SMBs face.

Ransomware: Modern strains don’t just encrypt servers, they search for mapped drives, NAS volumes, and accessible cloud buckets. Data stored on immutable storage can’t be altered, even if malware accesses them.

Accidental or intentional deletion: Human error remains a leading cause of data loss. A locked backup protects against an employee overwriting a directory or an attacker using stolen credentials to erase data.

Cyber insurance, compliance, and audit requirements: Cyber insurance policies as well as regulations in sectors like healthcare, financial services, legal, and government often require evidence that certain data has not been tampered with. Immutability provides that assurance.

For MSPs, immutability is ultimately about reducing risk and shortening recovery time. For SMBs, it’s about knowing that even in a worst-case scenario, there is still a very high chance that their data and systems can still be restored.

When SMBs Should Use Immutability — and When They Might Not Need It

Immutability is a powerful layer of protection, but that doesn’t mean every workload or every business requires it. For SMBs balancing cost, risk, and operational complexity, the goal is to apply immutability where it delivers real value, rather than applying it everywhere by default. The table below helps clarify when immutability meaningfully improves resilience, and when, for example, traditional backup versioning may already provide adequate protection.

In reality, there isn't a simple yes-or-no answer. Most SMBs benefit from a blended approach:

• Immutable backups for high-value, compliance-sensitive, or high-risk systems.
• Standard versioned backups for everyday operational workloads that don’t justify the cost or retention rigidity.

This targeted use of immutability gives MSPs and SMBs the resilience they need against modern threats without adding unnecessary complexity or cost.

What Types of Immutability Are Available

There are three ways MSPs and SMBs can leverage an immutable option as part of their overall backup strategy.

1. Storage-level immutability

This is the most common approach today, specifically for cloud storage. Object storage services allow data to be written once and locked for a defined period. During that window, nothing can delete or overwrite the data stored on the storage. When the retention time ends, the data stored here behaves like any other file.

2. Software-enforced immutability

Some backup platforms provide retention locks that prevent historic backup sets from being modified. This approach shields the backup chain even if, for example, individual files are being deleted or are compromised. NovaBACKUP uses a combination of retention settings and integrity checks that ensure if a file was removed from the backup set, it’s being backed up again to complete the selected data set and ensure its recoverability.

3. Air-gapped or offline copies

Although this is not technically "immutability," a disconnected copy is unchangeable because no third party can access the stored data. Just note that physical media can degrade over time or become unreadable if not stored properly. If you have an archive of tapes or exchangeable media, they need to be rotated on a regular basis. While this isn’t efficient for daily backups, it remains a trusted method in industries that prioritize physical separation.

How Immutability Fits into Your Backup Strategy

Immutability can be incorporated into various aspects of your backup strategy. When considering a hybrid backup approach where local backups serve as the primary source for quick recovery and cloud copies provide additional security, here's how to implement immutability for each layer:

Local backup: With NovaBACKUP, software-side immutability is included as part of the backup job, meaning, at the beginning of every scheduled job, NovaBACKUP checks if all files listed in the index are actually available on the storage and replaces anything that was deleted or corrupted. The local copy is then available for fast and easy restores.

Side note: Keep your local backups on a storage device that is only used for backups. For example, when using a NAS, make sure there’s only one set of credentials that have access and that the credentials are encrypted within the backup software. This provides an additional level of security to avoid access from unauthorized sources.

Cloud backup: In addition to software-side immutability for backups to the cloud, immutability is most often used in combination with cloud storage, meaning the storage itself can’t be edited.

Side note: if you decide to sign up for immutable cloud storage separately from your backup software, set the backup retention to the same timeframe as the immutable cloud storage to avoid unnecessary backup errors that occur from the software trying to enforce retention settings, but the storage preventing it.

Lastly, a hybrid backup architecture also helps balance cost and performance, keeping immutability affordable for SMB environments.

How MSPs Can Talk About Immutability With SMB Clients

Immutability can be an abstract concept and it’s not always straightforward to explain this security feature to SMBs. Immutability becomes easier to understand when framed around practical outcomes that matter to the business rather than listing technology features. A helpful approach is to focus on the why:

• It prevents scenarios where ransomware or a rogue actor destroys your backups.
• It gives you clean versions of your data even if the worst happens.
• It helps satisfy compliance and cyber insurance expectations.
• It reduces uncertainty during an outage or investigation.

The more concrete the explanation, the more clearly SMBs see immutability as a safety measure rather than a technical option.

Conclusion

Immutable backups are not a silver bullet, and they’re not required for every workload. But when used purposefully, they play a critical role in modern data protection, especially for small businesses trying to stay resilient in the face of increasing cyber threats.

For MSPs, immutability offers peace of mind that even if a breach reaches deep into a client’s environment, there will still be a clean, untouched copy of essential data. For SMBs, it’s an affordable way to ensure that their history of financial records, customer information, and business-critical applications remain intact and recoverable.

If you’d like guidance on implementing immutability as part of a broader hybrid backup strategy, contact us anytime. We’re happy to help you explore options that fit your environment and your clients’ needs.