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Considerations for File System Analytics

Contributors netapp-ahibbard netapp-aherbin
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You should be aware of certain usage limits and potential performance impacts associated with implementing File System Analytics.

SVM-protected relationships

If you have enabled File System Analytics on volumes whose containing SVM is in a protection relationship, the analytics data is not replicated to the destination SVM. If the source SVM must be resynchronized in a recovery operation, you must manually reenable analytics on desired volumes after recovery.

Performance considerations

In some cases, enabling File System Analytics could negatively impact performance during the initial metadata collection. This is most typically seen on systems that are at maximum utilization. To avoid enabling analytics on such systems, you can use ONTAP System Manager performance monitoring tools.

If you experience a notable increase in latency, refer to the Knowledge Base article High or fluctuating latency after turning on NetApp ONTAP File System Analytics.

Scan considerations

When you enable capacity analytics, ONTAP conducts an initialization scan for capacity analytics. The scan accesses metadata for all files in volumes for which capacity analytics is enabled. No file data is read during the scan. Beginning in ONTAP 9.14.1, you can track the progress of the scan with the REST API, in the Explorer tab of System Manager, or with the volume analytics show CLI command. If there is a throttling event, ONTAP provides a notification.

When enabling File System Analytics on a volume, ensure that at least 5 to 8 percent of the volume's available space is free. If the volume has autosize enabled, calculate the available size based on the maximum autogrow size. Beginning with ONTAP 9.15.1, ONTAP presents an error message if there's not enough space available when you enable File System Analytics on a volume.

After the scan completes, File System Analytics is continuously updated in real time as the file system changes.

The time required for the scan is proportional to the number of directories and files on the volume. Because the scan collects metadata, file size does not impact the scan time.

For more information about the initialization scan, see TR-4867: Best practice guidelines for File System Analytics.

Best practices

You should start the scan on volumes that do not share aggregates. You can see which aggregates are currently hosting which volumes using the command:

volume show -volume comma-separated-list_of_volumes -fields aggr-list

While the scan runs, volumes continue to serve client traffic. It's recommended you start the scan during periods where you anticipate lower client traffic.

If client traffic increases, it will consume system resources and cause the scan to take longer.

Beginning in ONTAP 9.12.1, you can pause data collection in System Manager and with the ONTAP CLI.

  • If you are using the ONTAP CLI:

    • You can pause data collection with the command: volume analytics initialization pause -vserver svm_name -volume volume_name

    • Once client traffic has slowed, you can resume data collection with the command: volume analytics initialization resume -vserver svm_name -volume volume_name

  • If you are using System Manager, in the Explorer view of the volume menu, you use the Pause Data Collection and Resume Data Collection buttons to manage the scan.