Storage Networking Times

Issue 7, January 2008

Standards Update:
SNIA’s New NDMP Technical Working Group
David Dale, Vice Chair, SNIA, info@snia.org

In December, the Storage Networking Industry Association announced the creation of a new Technical Working Group (TWG): “SNIA Creates Technical Work Group to Enhance NDMP Standard Through Software Development”. This signalled an expansion of SNIA’s portfolio of software development efforts, collectively targeted at expanding the universe of storage, storage management and data management interoperability tools.

For those of you who are not aware of NDMP, here’s a little background …

NDMP stands for Network Data Management Protocol and was created by a multi-vendor taskforce; the specification was made available through ndmp.org. Today, NDMP is the de facto standard protocol for NAS backup.

NDMP is fundamentally about data movement and its specification currently defines two services:

• A data server – which either reads from disk and produces an NDMP data stream (in a specified format), or reads an NDMP data stream and writes to disk, depending upon whether a backup or restore is taking place;
• A tape server – which reads an NDMP data stream and writes it to tape or reads from tape and writes an NDMP data stream, depending upon whether a backup or restore is taking place. All tape-handling functions, such as split-image issues, are dealt with by this service.

Each service has a separate state diagram that dictates its behavior, e.g. the tape server can enter the pause state while tapes are being changed by the NDMP client. NDMP messages are categorised into distinct groups or NDMP interfaces, such as SCSI, config and tape, and can trigger state changes.

The NDMP standard has evolved over time and has continued to mature with version 4. However, there is currently no consistent software development kit (SDK) that developers can use to implement this version of the specification. The new SNIA NDMP TWG is initially chartered to create an SDK for NDMP v4.0.

This software development effort was kick-started by significant code contributions, comprising the complete NDMP v3 reference implementation code base, donated to SNIA by NetApp and EMC. Other vendors who joined the NDMP TWG include Hitachi Data Systems, Pillar Data Systems, and Sun Microsystems.

The work product of the new NDMP TWG will help accelerate the already widespread adoption of the NDMP standard by storage vendors, and provide IT users in markets worldwide with more choices in data protection solutions.

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