Dell NetWorker 19.9 Administration Guide

Configuring multiplex backup to Data Domain VTL devices

Configure Data Domain VTL devices for multiple session backups as follows.

1. Shut down backup service on the NetWorker VTL storage node, or shut down the NetWorker server if that is possible, and verify that there is no backup activity on the storage node.
2. Use NMC or the nsradmin command to set the sessions values for each VTL device. The recommended values are as follows:
   • Max sessions=4 (32 maximum)
   • Target sessions=4
   • Device block size=512KB

   Optimal max sessions and device block size values depend on the environment. For example, max sessions=2 might provide better stability and deduplication while still meeting the backup window.
   NOTE: If you shut down the NetWorker server in step 1, you can run the nsradmin command with the -d resdir option. This option uses the NetWorker resource database, resdir, without opening a network connection.

   For example, on UNIX/Linux or Microsoft Windows systems, run the following command:

   nsradmin -i input_file.txt

   where input_file.txt is a text file that contains the following lines that you can customize to the own environment:

   option regexp: on
   . type: nsr device; media type: LTO Ultrium-3; media family: tape; name: /dev/rmt*
   update max sessions: 4; target sessions: 4; device block size: 512KB

3. Create a no intra-block multiplexing (nibmp) tag file in the NetWorker debug folder on the NetWorker storage node.

   For example, you can use the standard NetWorker installation paths for the tag file. You can limit the tag file path to a specific pool by adding the _poolname variable as a suffix to the tag file. The _poolname can include spaces, for example, _My Pool. On Microsoft Windows systems, ensure that the specified pathname is enclosed in quotes.

   Unix/Linux system examples.

   touch /nsr/debug/nibmp
   touch /nsr/debug/nibmp_My Pool

   Microsoft Windows system examples.

   echo > "NetWorker_install_path\nsr\debug\nibmp"
   echo > "NetWorker_install_path\nsr\debug\nibmp_My Pool"

4. Restart the NetWorker services to enable the multiplexing functionality.

   The technical note that is named , available on the Online Support website, provides more details.