High CPU load on pfSense VM running on Vultr VPS (KVM)

  • I am having performance issues with a pfSense 2.3.4 CE virtual machine installed on Vultr KVM (VPS provider), and I am hoping someone can help me determine the source of the issue.

    I have attached a few pictures for better visualization of this odd behaviour, but essentially the pfSense guest VM shows the CPU being mostly idle, while the Vultr control panel shows extremely high CPU usage during the exact same period of time.  On at least two occasions, I have lost access to the virtual machine (console, ssh and webui), and a hard reboot was required though the Vultr control panel.

    The only thing that I am really using on this pfsense VM is OpenVPN Server, for peer to peer network connection (AES-128-CBC, SHA1).  Also, it only has a single NIC.

    Is this a compatibility issue with the Virtio driver provided by KVM and FreeBSD? I have disabled offloading, so I know that's not the issue.  I am really trying to understand what is causing this CPU load, and how to fix this.

    I have read other posts about issues with Virtio and FreeBSD/pfSense but most conclude that disabling offloading corrects any issues.  So I am wondering if this is issue is related to compatibility or perhaps configuration on VPS provider side.

    Any help would be much appreciated.  The issue is occuring as I type this.

    ![vultr monitoring.png](/public/imported_attachments/1/vultr monitoring.png)
    ![vultr monitoring.png_thumb](/public/imported_attachments/1/vultr monitoring.png_thumb)
    ![pfsense monitoring.png](/public/imported_attachments/1/pfsense monitoring.png)
    ![pfsense monitoring.png_thumb](/public/imported_attachments/1/pfsense monitoring.png_thumb)

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