What happened to NDMP?

The acronym NDMP shows up once in a while in NAS (Network Attached Storage) upgrade tenders. And for the less informed, NDMP (Network Data Management Protocol) was one of the early NAS data management (more like data mover specifications) initiatives to backup NAS devices, especially the NAS appliances that run proprietary operating systems code.


Backup software vendors often have agents developed specifically for an operating system or an operating environment. But back in the mid-1990s, 2000s, the internal file structures of these proprietary vendors were less exposed, making it harder for backup vendors to develop agents for them. Furthermore, there was a need to simplify the data movements of NAS files between backup servers and the NAS as a client, to the media servers and eventually to the tape or disk targets. The dominant network at the time ran at 100Mbits/sec.

To overcome this, Network Appliance® and PDC Solutions/Legato® developed the NDMP protocol, allowing proprietary NAS devices to run a standardized client-server architecture with the NDMP server daemon in the NAS and the backup service running as an NDMP client. Here is a simplified look at the NDMP architecture.

NDMP Client-Server Architecture

NDMP Pains

By today’s demands and requirements, the unstructured files volume in NAS devices has proliferated to millions and billions of files. Changes to these files are more frequent and more rapid now.

Because of the nature of NDMP where it has to crawl through every single file object at every level of the directories in the NAS operating environment, the mechanism to maintain the incremental backup would mean checking each one of them before the backup server can initiate an actual data mover operation to move the changed files to the media server.

These “shortcomings” have lent the voice to the NDMP detractors that it is too slow and cannot scale. The implementation of encryption is more vendor specific, and access level security dates more to the Unix-style trusted environments.

The state of NDMP in 2021

Version 4 was the last key development of NDMP, and that was dated back to 2003. Today the custody and future development of NDMP (the last updated version was v5, but mostly additional extensions to the protocol) is under the foster care of SNIA®.

Skipping over NDMP

Many newer generation of data protection vendors have skipped NDMP in favour of their own data management methods to accelerate NAS backups. Changed block tracking (CBT) seems to be favoured by a few that I know, such as Veeam® and Cohesity, each with its own proprietary innovation to be a better NAS backup technology.

So, what happened to NDMP? It has certainly outlived its purpose, no longer serving its intended function in an ever growing NAS and file sharing market.


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About cfheoh

I am a technology blogger with 30 years of IT experience. I write heavily on technologies related to storage networking and data management because those are my areas of interest and expertise. I introduce technologies with the objectives to get readers to know the facts and use that knowledge to cut through the marketing hypes, FUD (fear, uncertainty and doubt) and other fancy stuff. Only then, there will be progress. I am involved in SNIA (Storage Networking Industry Association) and between 2013-2015, I was SNIA South Asia & SNIA Malaysia non-voting representation to SNIA Technical Council. I currently employed at iXsystems as their General Manager for Asia Pacific Japan.

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