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Best Practices for the NDMP Agent

Enable NDMP on NetApp File Server

Make sure that NDMP is enabled on the file server. This can be done in the following two ways:

Option 1: Command Line

  1. From a file server command line, run the ndmpd on command.

  2. Edit the /etc/rc file on the file server and add the command to the end of the file. This ensures that NDMP will be enabled each time the file server is rebooted.

Option 2: Web Browser

  1. From a standard web browser, enter the URL: http://filername/na_admin.

  2. Login using your login and password.

  3. Select NDMP.

  4. Click Enable NDMP.

    NDMP is now enabled and will start automatically each time the file server is rebooted. You can also configure CIFS shares and NFS exports.

Use UTF-8 Setting on NetApp for Volume Language

To successfully browse and restore NAS data on a NetApp file server, it is recommended to use the UTF-8 setting for volume language. If the volume language is not set to UTF-8, then foreign characters or Latin extended characters will not be displayed properly when the backup data is browsed. To restore these files or directories, the parent directory containing them will need to be restored.

Please consult with NetApp for implications of changing volume language.

NetApp iSCSI LUN Must Be Offline

For a NetApp iSCSI configuration, before restoring an iSCSI file from a NDMP backup job, the iSCSI LUN must be offline and the direct access restore (DAR) feature must be disabled. A LUN must be restored to a location supported by the NetApp file server such as the root of a volume or Qtree.

Use Load Balancing to Distribute Job Processes among Several Available MediaAgents

If you do not use Alternate Data Paths, do the following to allow job processes to be distributed among the different available MediaAgents:

  • Configure drive pools on multiple MediaAgents so that NAS jobs will not all run on a single MediaAgent, and thus the processor load for these jobs will occur on different machines. See Master Drive Pools, Drive Pools and Drives.

  • Configure multiple Storage Policies, each using a different MediaAgent and drive pool. See Storage Policies.

  • Distribute the data to be protected among multiple subclients.

  • Associate each subclient to a different Storage Policy. See Associate a Subclient to a Storage Policy.

If you do use Alternate Data Paths, the load-balancing of the job processes described above can be achieved just as effectively in addition to the network load-balancing and fault-tolerance that the Alternate Data Paths feature provides.

Reconfiguring Default Subclient Content

We recommend that you do not re-configure the content of a default subclient because this would disable its capability to serve as a catch-all entity for client data. As a result, some data will not get backed up or scanned.

Use IntelliSnap to Improve Backup Performance of Small Files

A bottleneck of too many read/write operations may occur when backing up small files to tape. Therefore, you may want to consider using IntelliSnap to create snapshots of these small files, instead of using regular NAS backups. Using snapshots may increase backup and restore performance in this case.

NAS Load Balancing

You can configure the drive pools, storage policies and subclients for NAS in such a way that different MediaAgents are used for backup, restore and auxiliary copy operations. Thus each operation will use resources from different computers.

Restores to a Windows or UNIX Client

Restores from supported NAS data backups to a Windows or UNIX client do not use the file server. For smaller amounts of data, these restores can be much faster than restores to the file server. However, restoring to a Windows or UNIX client has limitations.

The following are limitations for restoring NAS data to Windows or UNIX clients:

  • Dell EMC Unity: Restores from IntelliSnap backups are not supported.

  • Dell EMC VNX / Celerra:

    • Data deduplicated using the Celerra file system cannot be restored.

    • Restores from Celerra volume-based backup (VBB) are not supported.

    • Restores from IntelliSnap backups are not supported.

  • Empty folders are not restored.

  • Links within files may not be restored.

  • Offline files (stubs) are not restored.

  • Restores from NetApp SnapMirror to Tape (SMtape) backups are not supported.

  • Symlinks are restored only to the same or similar filer and appear as regular files while restoring to Windows or UNIX servers.

The following are limitations for restoring NAS data to Windows clients:

  • The user account used to restore the data must belong to the local administrator group on the Windows client so that the restore operation can read/write to a local path.

  • File and directory names with case differences will be treated like files and directories of the same name. This may cause one file/directory to overwrite another during the restore.

  • Files and directories with names containing UNIX-specific characters may have those characters replaced with a "_" character or have some other form of modification in the restored file/directory name.

  • Windows allows 1024 characters for filenames, including the path. A filename, including the path, with more than 1024 characters will not be restored to the Windows computer.

  • Restoring data to a UNC path or a mapped drive is not supported.

  • Links within files may not be restored.

The following are limitations for restoring NAS data to UNIX clients:

  • Restoring to an NFS-mounted file system is supported if you have the necessary permissions.

  • Links within files may not be restored.

  • When performing an out-of-place restore to Linux file system client, the permissions on the directories are not restored but permissions for files in these directories are restored.

Although restores to a Windows or UNIX client do not use a file server, this does not eliminate the need for a file server. Because of the limitations of restoring to a Windows and UNIX client, this method is not a replacement for having a file server available.

Restoring Files with Access Control Lists (ACLs)

Restores of files that contain Access Control Lists (ACLs) to Windows clients will include the backed up ACLs for the following vendors:

  • Dell EMC Isilon/PowerScale

  • Dell EMC PowerStore

  • Dell EMC Unity

  • Dell EMC VNX / Celerra

  • NetApp

For other file server vendors, files and directories that contain ACLs or permissions are restored but the ACLs are not restored.

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