Troubleshooting network issues - FSx for ONTAP
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Troubleshooting network issues

If you are experiencing network issues, you can use the procedures shown here to diagnose the problem.

You want to capture a packet trace

Packet tracing is the process of verifying the path of a packet through the layers to its destination. You control the packet tracing process with the following NetApp ONTAP CLI commands:

  • network tcpdump start – Starts packet tracing

  • network tcpdump show – Shows currently running packet traces

  • network tcpdump stop – Stops a running packet trace

These commands are available to users who have the fsxadmin role on your file system.

To capture a packet trace from your file system
  1. To SSH into the NetApp ONTAP CLI of your file system, follow the steps documented in the Using the NetApp ONTAP CLI section of the Amazon FSx for NetApp ONTAP User Guide.

    ssh fsxadmin@file-system-management-endpoint-ip-address
  2. Enter the diagnostic privilege level in the ONTAP CLI by using the following command.

    ::> set diag

    When prompted to continue, enter y.

    Warning: These diagnostic commands are for use by NetApp personnel only.
    Do you want to continue? {y|n}: y
  3. Identify the location on your file system where you want to save your packet trace. The volume must be online and must be mounted in the namespace with a valid junction path. Use the following command to check for volumes that fulfill those criteria:

    ::*> volume show -junction-path !- -fields junction-path vserver volume junction-path ------- --------- ------------- fsx test_vol1 /test_vol1 fsx test_vol2 /test_vol2 fsx test_vol2 /test_vol3
  4. Start the trace with the minimum required arguments. Replace the following:

    • Replace node_name with the name of the node (for example, FsxId01234567890abcdef-01).

    • Replace svm_name with the name of your storage virtual machine (for example, fsx).

    • Replace junction_path_name with the name of the volume (for example, test-vol1).

    ::*> debug network tcpdump start -node node_name -ipspace Default -pass-through "-i e0e -w /clus/svm_name/junction_path_name" Info: Started network trace on interface "e0e" Warning: Snapshots should be disabled on the tcpdump destination volume while packet traces are occurring. Use the "volume modify -snapshot-policy none -vserver fsx -volume test_vol1" command to disable Snapshots on the tcpdump destination volume.

    Packet traces can only be captured on the e0e interface and in the Default IP space. In FSx for ONTAP, all network traffic uses the e0e interface.

    When using packet tracing, keep the following in mind:

    • When starting a packet trace, you must include the path to where you want to store the trace files, in this format: /clus/svm_name/junction-path-name

    • Optionally, provide the file name for the packet trace. If the filter_name is not specified, it is automatically generated in the form: node-name_port-name_yyyymmdd_hhmmss.trc

    • If rolling traces are specified, the filter_name is suffixed with a number that indicates the position in the rotation sequence.

    • The ONTAP CLI also accepts the following optional -pass-through arguments:

      -B, --buffer-size=<KiB> -c <number_of_packets> -C <file_size-mB> -F <filter_expression_filename> -G <rotate_seconds> --time-stamp-precision {micro|nano} -Q, --direction {in|out|inout} -s, --snapshot-length=<bytes> -U, --packet-buffered -W <rotate_file_count> <filter-expression>
    • For information about filter expressions, see pcap-filter(7) man page.

  5. View the traces in progress:

    ::*> debug network tcpdump show Node IPspace Port Filename ----------------------- -------- -------- -------- FsxId123456789abcdef-01 Default e0e /clus/fsx/test_vol1/FsxId123456789abcdef-01_e0e_20230605_181451.trc
  6. Stop the trace:

    ::*> debug network tcpdump stop -node FsxId123456789abcdef-01 -ipspace Default -port e0e Info: Stopped network trace on interface "e0e"
  7. Return to the admin privilege level:

    ::*> set -priv admin ::>
  8. Access the packet traces.

    Your packet traces are stored in the volume that you specified using the debug network tcpdump start command, and can be accessed via the NFS export or an SMB share that corresponds with that volume.

For more information about capturing packet traces, see How to use debug network tcpdump in ONTAP 9.10+ in the NetApp Knowledge Base.