NDMP acceptance growing

Posted on February 01, 2002


By Lisa Coleman

The Network Data Management Protocol (NDMP) is expected to gain a stronger foothold in the end-user community as several vendors plan to ship products compliant with the latest Version 4.0 specification over the next quarter.

NDMP defines a network-based mechanism and protocol for controlling backup, recovery, and other data transfers between primary and secondary storage devices. Although NDMP is typically associated with network-attached storage (NAS), it is not necessarily limited to NAS configurations.

The Internet Engineering Task Force (IETF) was expected to initiate a workgroup to address NDMP last month. However, at press time the IETF was still debating whether or not to form the workgroup.

NDMP started as a grassroots campaign that evolved into a working group within the backup group at the Storage Networking Industry Association (SNIA). NDMP supporters then submitted a draft to IETF. They chose IETF because NDMP is being used over the Internet and in corporate networks-not just in local IT environments.

"The evolution of NDMP needs to be increasingly focused on areas that are in the IETF domain, such as security and congestion control," says Greg Linn, engineering development manager responsible for NDMP at Network Appliance, one of the companies that originally spearheaded NDMP. "There's a significant amount of expertise and work that has already been done that NDMP could benefit from, and that's why we see the move into the IETF as being very beneficial," he adds.

If initiated, the IETF NDMP workgroup will develop version 5.0 and hopes to complete the spec within the next 18 months. The workgroup is paring down a "wish list" of potential requirements for the protocol and plans to focus on a subset of the original list, according to Linn.

Some areas of focus for NDMP 5.0 are security issues such as authentication for authorized peer communication and operation across firewall environments. NDMP involves either two or three peers depending on the topology. "There's a need to improve the authentication that's provided to identify authorized peers to talk to each other," says Linn. While NMDP does support a few methods of authentication, more recent methods could be leveraged in the next version, he adds.

Another area that Linn wants to explore is checkpoints in "restartability." Currently, a user may start a backup operation and, depending on the dataset that is backed up, it may take hours to complete, according to Linn. If a failure occurs during that operation-it could be as simple as having a bad tape in a tape drive or the tape drive itself being down-there is no way to go back to the last known "good" point within the backup stream. The operation must be restarted. "We want to provide a checkpointing and restartability mechanism where periodically we can say 'the data was good and it was recorded up to this point,' " explains Linn.

The NDMP workgroup will also examine more-reliable operation over networks. This will include improved timeout handling and control and management of snapshot operations. Linn expects that further versions of NDMP will create more extensions to communicate to vendor-specific functions.

Today, about 20 vendors support NDMP, including most of the backup application vendors. "From a backup perspective, it's becoming more ubiquitous," says Linn. "Hopefully, we'll see more device manufacturers adopt NDMP over the course of the next year or two." For a list of NDMP-supported products, visit www.ndmp.org.

Product enhancements

Network Appliance is shipping NDMP V4.0 in the 6.1.2 release of its DataOnTap operating system. The next major release will include the V4.0 extension for snapshot management. "NDMP allows backup application vendors to directly control the snapshot process on the filer," explains Linn. In the past, the application vendor would invoke a backup operation while the NAS backup logic would take a snapshot and pull the data out of that snapshot and pass it to the tape device designated by the backup application. With snapshot management control resident at the backup application, application vendors can use the NAS snapshot as an alternative to a traditional tape-based backup for near-line storage, says Linn.

About a year ago, Procom Technology started supporting NDMP because it offered speed and simplicity for its NAS filers. Procom began by working with Veritas' NetBackup and has expanded its supported software to include BakBone, Computer Associates, Legato, and Syncsort.

Computer Associates has been supporting NDMP since last July. Within the next two months, CA will add support for multiple NAS devices and tape library functionality in its ARCserve product. "In the NAS space, NDMP will be the standard in the future," predicts Marco Coulter, divisional vice president for storage at CA.

Veritas has supported NDMP as an option with NetBackup for more than three years. Over that period, Veritas has added support for more-complex NDMP configurations and is continuing its efforts to enhance the reliability and performance of its NDMP products. In March, Veritas will ship NetBackup for NDMP V4.5, which will support three-way NDMP backup from NAS devices to a library attached to a NetBackup media server. Its NDMP tape mover agent will run independently of NetBackup and permits three-way backups directly to NetBackup rather than to a NAS device with attached tape devices.

Within the next few months, Syncsort will add new features to its NDMP interface software. Currently, it supports direct-attached and local backup in addition to three-way and filer-to-filer backup. In March, the company will introduce server-to-filer support, as well as support for the eight incrementals that NDMP versions 2, 3, and 4 enable. Also, filer-to-server support will be expanded to include Solaris, Linux, and True64.

This month, BakBone Software released NetVault 6.7, which includes new NDMP features such as snapshot management and snap mirror management for Network Appliance filers.

Next month, Workstation Solutions will release Quick Restore Version 3. Each client will be NDMP-enabled, and NDMP processing will be streamlined to move data directly from the source to its destination without involving a third host.

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