NetVault Backup 9.2 and above comes with the RDA plugin installed. If the DR Appliance has been upgraded to a higher version, the plugin should be upgraded to match. You can check the version by going to device management, right clicking on the DR appliance and selecting Status. Under the Device tab it will show the DR OS version and the Client RDA API version. These should match.
If the RDA plugin version on the client doesn't match the DR OS version it may cause backups to fail.
Error 2014/05/01 06:15:20 99 Data Plugin NVBUSERVER Failed to open a RDA connection to 'DR4100'. Error Code 6. 'Operation failed'
Error 2014/05/01 06:15:20 99 Data Plugin NVBUSERVER Failed to open a RDA connection to 'DR4100'. Please review the RDA device details.
Log context states;
RDA Library error code: 0
1. Login to the DR appliance web interface
2. Go to Storage | Clients
3. In the top right corner click on the link to "Download Plug-in"
4. For Windows download RDS Windows (32-bit & 64-bit) DellRDSPlugin-X.X.XXXX.X.exe
5. Copy DellRDSPlugin-X.X.XXXX.X.exe to the computer where you will upgrade the plugin.
6. Stop the NetVault Service. Open NVBU configurator. In the Service tab click on "Stop Service"
7. Execute the installer DellRDSPlugin-X.X.XXXX.X.exe
8. Start the NetVault service. Open NVBU configurator. In the Service tab click on "Start Service"