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EMS callhome.arw.activity.seen alerts for SAN volumes

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Category:
ontap-9
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core
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Applies to

  • ONTAP 9.17 and later
  • AFF & FAS systems 

Issue

  • ONTAP generated repeated EMS alerts:
    Node:svc_queue_thread:callhome.arw.activity.seen:alert]: Callhome message for "POSSIBLE RANSOMWARE ACTIVITY DETECTED", Volume: "vol1" in Vserver: "vserver1"
  • Genearting an ARP attack report for the affected volume fail with:
    Error: command failed: Operation is not supported on volumes that contain LUNs or namespaces.
  • The detected encryption percentage (53%) slightly exceeded the auto-learned threshold (52%) for a short interval.
    cluster1::*> security anti-ransomware volume entropy-stat show-recent-high-encryption-stat -vserver vserver1 -volume vol1
    Vserver         Volume         StartTime           Duration   DataWritten   Data%
    vserver1          vol1         7/29/2026 07:15:05  0h10m0s    1.60GB         53%
  • No ARW alerts on other volumes; no sustained high-entropy activity observed.

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