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What are the OnCommand Unified Manager (DFM) discovery issues and how can they be resolved?

Applies to

OnCommand Unified Manager 5.x

Answer

  • OnCommand Unified Manager (DFM) not discovering the controller
  • OnCommand Unified Manager (DFM) is not discovering Logical Unit Number (LUN)
  • Manual discovery of OnCommand Unified Manager (Operations Manager) (previously DFM)

OnCommand Unified Manager (DFM) uses SNMP for host discovery and monitoring. By default, discovery is enabled and configured to discover appliances on the same subnet as the OnCommand Core Unified Manager (DFM). The host discovery SNMP query supplies OnCommand Unified Manager (DFM) with the information it requires to monitor and manage an appliance. The default interval for the discovery process is every 15 minutes.

When a new controller or cluster is added to the storage environment, the OnCommand Unified Manager (DFM) administrator can either wait for the discovery cycle, or manually add the host through ‘dfm host add <hostname or ip address>’. When adding a clustered Data ONTAP you must specify the IP address of the cluster management LIF.

OnCommand Unified Manager (DFM) is capable of both Host and Network Discovery:

  • If Host Discovery is enabled, OnCommand Unified Manager (DFM) will issue an SNMP GET to all hosts on the local network. Any device that replies and is identified as a NetApp appliance is automatically added to the OnCommand Unified Manager (DFM) database.

    Note: Having the discoverHosts option enabled might cause undesired SNMP traffic on the network and add to the overall system load for both the OnCommand Core Unified Manager (DFM) as well as the monitored hosts. After the initial OnCommand Unified Manager (DFM) installation and setup is complete, execute  the dfm option set discoverHosts=Disabled command or alternatively follow these steps within the UI:

Perform the following steps for OnCommand Unified Manager (DFM) within the NetApp OnCommand console:

  1. Navigate to Administration > Setup Options.
  2. Expand Discovery then select Options.
  3. Clear any Host Discovery check-boxes for objects that is not to be automatically discovered on the network.
  4. Click Save and Close.

For OnCommand Unified Manager (DFM), within the Operations Manager web interface:

  1. Navigate to Setup > Options.
  2. Select Discovery.
  3. Set the drop down boxes to Disabled for objects that need not be automatically discovered on the network.
  4. Click Update.
  • If Network Discovery is enabled, OnCommand Unified Manager (DFM) will issue an SNMP GET request to all hosts on the local network. Any device that replies and is identified as a network router is then queried again by OnCommand Unified Manager (DFM) to gather information on the other networks to which this router might be attached. OnCommand Unified Manager (DFM) will continue to discover networks and the appliances on these networks using SNMP. 

For additional information on configuring and controlling OnCommand Unified Manager (DFM) discovery functions, see DataFabric Manager Administration Guide.

Perform the following steps to resolve the discovery issues noted above:

  • If OnCommand Unified Manager (DFM) is located on a different subnet than the NetApp appliance:
    • Verify the network router/firewall permits the SNMP protocol between DFM and the NetApp appliances.
    • Verify that Network Discovery is enabled in OnCommand Unified Manager (DFM) and the hop count is not exceeded.
    • If Network Discovery is disabled, verify that the appliance's subnet is added to the list of Discovered Networks in OnCommand Unified Manager (DFM)
  • If SNMP is not enabled on the controller:
    • To check if SNMP is enabled on the controller:
      filer> options snmp.enable
    • To enable SNMP on the controller:
      filer> options snmp.enable on
  • If the SNMP community string on the controller does not match the SNMP string configured in OnCommand Unified Manager (DFM):
    • On the controller:
      • Check the current SNMP string:
        filer> snmp community
      • Set a new/additional SNMP community string:
        filer> snmp community add ro <community>
      • To delete an existing SNMP community string:
        filer> snmp community delete ro <community>
    • In OnCommand Unified Manager (DFM):
      • To check the SNMP community string configured in OnCommand Unified Manager (DFM):
        • CLI:
          dfm# dfm snmp list
        • Web GUI:
          Go to Options link > Discovery Options > SNMP Communities > Edit link

Note: Having the discoverHosts option enabled might add to the overall system load. After the initial OnCommand Unified Manager (DFM) installation and setup is complete, run the dfm option set discoverHosts=Disabled command.

Additional Information

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