RecoveryLab Data Recovery explains why redundancy and data backup are two different things

Many businesses now have a NAS with a RAID array. These devices are quick to set up, can be accessed centrally and, depending on the configuration, offer important protection against failure. Yet this is precisely where a common misconception lies: a RAID array can improve availability, but it is no substitute for a backup.

A RAID array primarily protects against specific hardware failures. A RAID 1 mirrors data across at least two drives. A RAID 5 distributes user data and parity information across at least three drives and can tolerate the failure of a single drive. If a hard drive fails, the system can continue to run under the right conditions. This is precisely what this architecture is designed for.

What a RAID does not do, however, is protect against every data loss scenario. Things become critical when several drives fail simultaneously or in an unfavourable combination, when firmware errors render the entire volume inaccessible, or when logical inconsistencies arise following abrupt write interruptions. Nor does RAID prevent accidental deletion, ransomware or physical damage to the device.

The key difference: RAID operates within the production system. Any change to the data, whether due to user error or malware, is immediately propagated across the array. RAID does not assess whether a change is intentional, erroneous or malicious.

What the figures show

The fact that the difference between backup and actual recoverability is underestimated in many companies is also demonstrated by the 2025 SME Backup Study by DATA REVERSE® Data Recovery. For the study, 285 small and medium-sized enterprises were surveyed about their backup practices.

77 per cent of respondents back up their data at least weekly, 24 per cent even daily. At the same time, 72 per cent stated that they rarely or never check the functionality of their backups. This is precisely where the risk lies: a backup is only reliable if not only the backup itself but also the recovery process works.

Hybrid solutions combining cloud and local storage must also be carefully planned. The crucial factor is whether the local storage actually serves as an independent backup copy or is merely operated as another permanently connected NAS on the network.

What constitutes a robust backup strategy

A robust backup strategy requires more than just redundancy. It must be separate from the production system, protected against unintended changes, and tested regularly.

The well-known 3-2-1 rule describes this approach: three copies of the data, on two different types of media, with one copy off-site. A NAS can be part of such a strategy. However, it must not be confused with the entire strategy.

Restore testing is also important. A backup is only robust if not only the backup itself but also the restore process has been successfully tested. Particularly in a corporate environment, what matters in an emergency is not simply whether data has been stored somewhere, but whether it can be made available again quickly, completely and in a structured manner.

RecoveryLab: Data recovery when redundancy and backup are not enough

RecoveryLab, based in Bonn, has been carrying out professional data recovery for over 20 years. The laboratory regularly encounters cases where NAS and RAID systems have failed, even though they were originally intended as secure storage solutions.

Typical causes include faulty hard drives, damaged RAID metadata, faulty firmware processes, interrupted write operations or logical damage to the file system. The situation becomes particularly critical when no independent, verified backup exists and business-critical data is only stored on the affected NAS system.

‘A RAID makes sense, but it is no substitute for data backup,’ explains RecoveryLab Data Recovery. ‘It can increase availability, but it does not protect against all causes of data loss. Companies should therefore make a clear distinction between redundancy, backup and recoverability.’

Those who use a NAS as a central storage system and also maintain an independent, tested backup significantly reduce their risk. Those who, on the other hand, regard the NAS both as a production system and as their sole backup often only realise the vulnerability when it is too late.