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Does the SAN ARP entropy evaluation period apply to NAS volumes including VM datastores ?

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Applies to

  • ONTAP 9
  • Autonomous Ransomware Protection (ARP)
  • SAN volumes (iSCSI, FC, NVMe LUNs)
  • NAS volumes (NFS, CIFS, including VM datastores for VMware, Hyper-V, KVM)

Answer

  • No. The SAN ARP entropy evaluation period does not apply to NAS volumes, including NAS-hosted VM datastores with virtual disks.
  • ARP evaluation period (Entropy Evaluation Period) is introduced for SAN volumes in ONTAP 9.17.1.
    • Applies only to block storage workloads (LUNs over iSCSI, FC, NVMe).
    • Required due to unique entropy characteristics of SAN workloads.
    • Evaluation period assesses suitability for ransomware protection.
  • NAS volumes, including those used as VM datastores (with virtual disks from hypervisors such as VMware, Hyper-V, KVM), do not use the SAN-specific ARP evaluation period.
  • NAS volumes have supported ARP prior to ONTAP 9.17.1.
  • No separate evaluation period process is implemented for NAS volumes.
  • ARP for NAS volumes operates using file-based telemetry (file creation, renaming, extension changes, file entropy).
  • ONTAP 9.17.1 enhances ARP support for VM datastores on NAS, but does not apply SAN evaluation period requirements to these volumes.
  • SAN-specific evaluation period and consistency group restrictions (such as those for NVMe) do not apply to NAS or VM datastore volumes.
  • VM datastores on NAS are treated as standard NAS volumes for ARP purposes, even if they hold virtual disk files (VMDK, VDI, VHDX).

Additional Information

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