I keep offline backups of my server. I use a bunch of USB 3.0 HDDs. So basically I 3-2-1 the HDs and rotate them to an offsite location. The problem is that if the windows 10 VM is running and I want to use them in the WIndows 10 VM. So without taking the VM down, I go into "edit" then check the new disk in the list of devices at the bottom. Every time I do this I get an error message. However, the drive is available in WIndows 10. The big problem is if I take the VM offline and then back online for any reason and that drive is no longer plugged in, I cannot start the VM. Since each drive is offsite 1/3 of the time, if this happens with a drive that I don't have on hand, I have to delete that VM and create a new one. This has happened so many times that I just have a copy of the working XML and make new one. This is more of a nuisance but I was just wondering if anyone had any insight on to why this is happening? Thanks!!!

 

```<?xml version='1.0' encoding='UTF-8'?>
<domain type='kvm' id='4'>
  <name>Windows 10</name>
  <uuid>redacted</uuid>
  <metadata>
    <vmtemplate xmlns="unraid" name="Windows 10" icon="windows.png" os="windows10"/>
  </metadata>
  <memory unit='KiB'>24641536</memory>
  <currentMemory unit='KiB'>24641536</currentMemory>
  <memoryBacking>
    <nosharepages/>
  </memoryBacking>
  <vcpu placement='static'>14</vcpu>
  <cputune>
    <vcpupin vcpu='0' cpuset='0'/>
    <vcpupin vcpu='1' cpuset='1'/>
    <vcpupin vcpu='2' cpuset='9'/>
    <vcpupin vcpu='3' cpuset='2'/>
    <vcpupin vcpu='4' cpuset='3'/>
    <vcpupin vcpu='5' cpuset='11'/>
    <vcpupin vcpu='6' cpuset='4'/>
    <vcpupin vcpu='7' cpuset='12'/>
    <vcpupin vcpu='8' cpuset='5'/>
    <vcpupin vcpu='9' cpuset='13'/>
    <vcpupin vcpu='10' cpuset='6'/>
    <vcpupin vcpu='11' cpuset='14'/>
    <vcpupin vcpu='12' cpuset='7'/>
    <vcpupin vcpu='13' cpuset='15'/>
  </cputune>
  <resource>
    <partition>/machine</partition>
  </resource>
  <os>
    <type arch='x86_64' machine='pc-i440fx-4.2'>hvm</type>
    <loader readonly='yes' type='pflash'>/usr/share/qemu/ovmf-x64/OVMF_CODE-pure-efi.fd</loader>
    <nvram>/etc/libvirt/qemu/nvram/093dfbb6-48ed-1881-69e7-706db34f9cf2_VARS-pure-efi.fd</nvram>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <hyperv>
      <relaxed state='on'/>
      <vapic state='on'/>
      <spinlocks state='on' retries='8191'/>
      <vendor_id state='on' value='none'/>
    </hyperv>
  </features>
  <cpu mode='host-passthrough' check='none'>
    <topology sockets='1' cores='7' threads='2'/>
    <cache mode='passthrough'/>
  </cpu>
  <clock offset='localtime'>
    <timer name='hypervclock' present='yes'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/local/sbin/qemu</emulator>
    <controller type='virtio-serial' index='0'>
      <alias name='virtio-serial0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'>
      <alias name='pci.0'/>
    </controller>
    <controller type='usb' index='0' model='qemu-xhci' ports='15'>
      <alias name='usb'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </controller>
    <interface type='bridge'>
      <mac address='redacted'/>
      <source bridge='br0'/>
      <target dev='vnet0'/>
      <model type='virtio'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </interface>
    <serial type='pty'>
      <source path='/dev/pts/0'/>
      <target type='isa-serial' port='0'>
        <model name='isa-serial'/>
      </target>
      <alias name='serial0'/>
    </serial>
    <console type='pty' tty='/dev/pts/0'>
      <source path='/dev/pts/0'/>
      <target type='serial' port='0'/>
      <alias name='serial0'/>
    </console>
    <channel type='unix'>
      <source mode='bind' path='/var/lib/libvirt/qemu/channel/target/domain-4-Windows 10/org.qemu.guest_agent.0'/>
      <target type='virtio' name='org.qemu.guest_agent.0' state='disconnected'/>
      <alias name='channel0'/>
      <address type='virtio-serial' controller='0' bus='0' port='1'/>
    </channel>
    <input type='mouse' bus='ps2'>
      <alias name='input0'/>
    </input>
    <input type='keyboard' bus='ps2'>
      <alias name='input1'/>
    </input>
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <driver name='vfio'/>
      <source>
        <address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
      </source>
      <alias name='hostdev1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </hostdev>
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <driver name='vfio'/>
      <source>
        <address domain='0x0000' bus='0x00' slot='0x1f' function='0x3'/>
      </source>
      <alias name='hostdev2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </hostdev>
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <driver name='vfio'/>
      <source>
        <address domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
      </source>
      <alias name='hostdev3'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </hostdev>
    <hostdev mode='subsystem' type='usb' managed='no'>
      <source>
        <vendor id='0x0c45'/>
        <product id='0x7403'/>
        <address bus='1' device='6'/>
      </source>
      <alias name='hostdev4'/>
      <address type='usb' bus='0' port='1'/>
    </hostdev>
    <hostdev mode='subsystem' type='usb' managed='no'>
      <source>
        <vendor id='0x1038'/>
        <product id='0x1824'/>
        <address bus='1' device='5'/>
      </source>
      <alias name='hostdev5'/>
      <address type='usb' bus='0' port='2'/>
    </hostdev>
    <hostdev mode='subsystem' type='usb' managed='no'>
      <source startupPolicy='optional'>
        <vendor id='0x1058'/>
        <product id='0x25a3'/>
        <address bus='2' device='15'/>
      </source>
      <alias name='hostdev6'/>
      <address type='usb' bus='0' port='4'/>
    </hostdev>
    <memballoon model='none'/>
  </devices>
  <seclabel type='dynamic' model='dac' relabel='yes'>
    <label>+0:+100</label>
    <imagelabel>+0:+100</imagelabel>
  </seclabel>
</domain>```

It's "normal" but obviously undesirable behaviour.

 

Until something changes in the way Unraid handles USB devices that are attached to the host, I recommend finding a way to pass through an entire USB controller to the VM. If your motherboard doesn't have multiple discreet controllers that can be individually passed to a VM, you would need to add a PCIe USB card. This video is somewhat outdated, but the basics are sound.

 

Thanks!! Yeah. That's what I thought. Maybe a tape drive is in my future.  I'm using an Intel Z390 (being an old man, it was hard to move to a threadripper, in retrospect...) and one of my bonds for gigabit is over thrunderbolt 3 (due to my lack of faith in Intel built-in RJ45), two video cards, two SATA PCI-e cards and I'm using the front USB 3.0 for the Unraid thumbdrive.