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NAS backup: Which suppliers have gone post-NDMP?

NAS backup with NDMP has many drawbacks so some vendors have moved to a data management approach that tracks changes and allows for incremental forever protection

We recently looked at the problem with NAS backup and got an idea what some vendors are doing to backup the kind of unstructured file data that is becoming more commonplace in numerous workloads today.

In short, the issue with NAS revolves around the sheer volume of files/data they can hold but crucially with how NAS backup works.

For years the best way to do it – and it’s still a very commonly-used solution – is to use Network Data Management Protocol (NDMP). This allows backups to be controlled from a discrete backup server and traffic to be routed to dedicated backup media (fundamentally tape, although disk-based virtual tape is also possible). But, there are still a host of data incompatibility issues between NAS vendors.

In this article we take a look at some key backup vendors and see where they’re at in terms of dealing with NAS backup.

The big picture that emerges is that some base their approach on NDMP and some have moved to a new way of working that’s based on tracking changes in file data.

NDMP-based NAS backup

In the first camp we find the more established backup product makers.

Products such as Veritas’s NetBackup and BackupExec, Commvault, IBM Tivoli Storage Manager (TSM), HPE Data Protector, EMC’s Avamar and Networker, and Arcserve are all firmly in the NDMP camp.

Products like these often allow for multiple vendor’s NAS as a backup source via agents and often lay claim to offers of point-in-time and cross-platform restore (such as Commvault). File and folder-level restore is also offered (by the likes of IBM’s TSM, for example).

Non-NDMP NAS backup

Where things have changed is among the vendors that offer non-NDMP approaches to NAS backup.

Changed data tracking emerged with Rubrik and Cohesity in what looks more like the functions of a data management platform rather than backup as we have known it. This sees files tracked for changes with only changed files taken as part of the backup. That’s quite a different approach and allows for incremental forever protection, which wasn’t possible with NDMP.

That way of working has been adopted by Veeam, in what could be seen as the first of the “traditional” backup software makers to move beyond NDMP-based NAS backup.

The data management approach is taken further by Igneous, which offers that functionality discretely, and also allows for the copy of backup to become the move of archiving.


Veeam added NAS backup to its version 10 of its Availability Suite in February, calling it a “monumental achievement”.

The company has tackled the limitations of NDMP with what it calls changed file tracking, which is based on changed block tracking in VMware and makes incremental forever backup via NDMP possible in Veeam.

Changed file tracking keeps a record of the source file system in a so-called cache repository and monitors changes between backups.

Read more about NAS backup

Veeam can backup NAS on Windows and Linux file servers and via NFS and SMB. It can also create backups from storage snapshots on NAS systems, and can rollback to previous states and recover files and folders.

Recovery can be “restore entire share”, rollback to a point in time or individual files and folders.


Rubrik has had NDMP-free NAS backup that is incremental forever and which stores data in its native format since its 3.0 Firefly release in early 2017 and can stage data off to cloud archives.

Its approach is based on tracking changes in data held on NAS systems and copying data from there to the backup target.

Rubrik also offers a way of monitoring permission errors. These are when data goes un-backed up due to lack of permissions. Rubrik collates a downloadable CSV file that lists these so action can be taken.

Search and recovery is granular down to file level and via a web GUI.

Rubrik doesn’t offer the ability to backup NAS vendor storage snapshots, and cites difficulties that can come with that approach. These include, it says, use of NAS capacity to keep the snapshots as well as added complexity due to managing backups and NAS devices.


Cohesity tracks changed files in NAS volumes and takes a full backup followed by incremental forevers. Data is kept in a hydrated form on the Cohesity Data Platform so it can be recovered quickly, with metadata indexed for rapid access.

It can protect data in any NAS product, but offers extended functionality to NetApp, Dell EMC and Pure Storage products, such as advanced snapshot management in the array from the Cohesity UI.

NAS backups are integrated into the Cohesity UI as a data type and policies can be implemented. Global data deduplication can help to cut data volumes across multiple NAS backups.

Full volume or single file recovery is possible.

Data can be tiered or archived to public cloud services that include Google Cloud Storage Nearline, Microsoft Azure, Amazon S3 and Glacier.


Igneous also bases its offer around something that looks more like a data management platform that scans NAS systems, builds indexes, tracks changes and moves and/or copies data off, to local appliances (virtual or physical) and the cloud.

Its emphasis is on the as-a-service nature of its offer and use of the cloud as a target, and deployments can be distributed.

It can work with any NAS system, but has deeper functionality with NetApp, Dell EMC Isilon and Pure Storage hardware. There’s quite a lot of compute work carried out during scans, moves etc so Igneous can throttle itself back so that production systems are not affected.

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