OneFS NDMP Backup Overview
Fri, 15 Dec 2023 15:00:00 -0000
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NDMP (Network Data Management Protocol) specifies a common architecture and data format for backups and restores of NAS (Network Attached Storage), allowing heterogeneous network file servers to directly communicate to tape devices for backup and restore operations. NDMP addresses the problems caused by the integrations of different backup software or DMA (Data Management Applications), file servers, and tape devices.
The NDMP architecture is a client/server model with the following characteristics:
- The NDMP host is a file server that is being protected with an NDMP backup solution.
- The NDMP server is a virtual state machine on the NDMP host that is controlled using NDMP.
- The backup software is considered as a client to the NDMP server.
OneFS supports the following two types of NDMP backups:
- NDMP two-way backup
- NDMP three-way backup
In both backup models, OneFS takes a snapshot of the backup directory to ensure consistency of data. The backup operates on the snapshot instead of the source directory, which allows users to continue read/write activities as normal. OneFS makes entries in the file history that are transferred from the PowerScale cluster to the backup server during the backup.
NDMP two-way backup
The NDMP two-way backup is also known as the local or direct NDMP backup, which is considered the most efficient model and usually provides the best performance. The backup moves the backup data directly from the PowerScale cluster to the tape devices without moving to the backup server over the network.
In this model, OneFS must detect the tape devices before you back up data to them. The PowerScale cluster provides the option for NDMP two-way backups as shown in the following figure. You can connect the PowerScale cluster to a Backup Accelerator node and connect tape devices to that node. The Backup Accelerator node is synonymous with a Fibre Attached Storage node without adding primary storage and offloads NDMP workloads from the primary storage nodes. You can directly connect tape devices to the Fibre Channel ports on the PowerScale cluster or Backup Accelerator node using Fibre Channel. Alternatively, you can connect Fibre Channel switches to the Fibre Channel ports that connect tape devices to the PowerScale cluster or Backup Accelerator node.
The following table shows details of the NDMP two-way backup supported by PowerScale:
NDMP two-way backup option | Generation 5 PowerScale nodes with an InfiniBand back end | Generation 6+ PowerScale nodes with an InfiniBand back end | Generation 6+ PowerScale nodes with an Ethernet back end |
B100 backup accelerator | Supported | Supported | Supported |
Note: The B100 backup accelerator requires OneFS 9.3.0.0 or later.
NDMP three-way backup
The NDMP three-way backup, also known as the remote NDMP backup, is shown in the following figure.
In this backup mode, the tape devices are connected to the backup media server. OneFS does not detect tape devices on the PowerScale cluster, and Fibre Channel ports are not required on the PowerScale cluster. The NDMP service runs on the NDMP server or the PowerScale cluster. The NDMP tape service runs on the backup media server. A DMA on the backup server instructs the PowerScale cluster to start backing up data from the PowerScale cluster to the backup media server over the network. The backup media server moves the backup data to tape devices. Both servers are connected to each other across the network boundary. Sometimes, the backup server and backup media server reside on the same physical machine.
For some specific DMA, DMA can write NDMP data to non-NDMP devices. For example, Dell NetWorker software writes NDMP data to non-NDMP devices, including tape, virtual tape, Advanced File Type Device (AFTD), and Dell PowerProtect DD series appliances. For more information on Data Protection with Dell NetWorker using NDMP, refer to this guide: Dell PowerScale: Data Protection with Dell NetWorker using NDMP.
Author: Jason He, Principal Engineering Technologist