Pass a Physical Disk Through to a Proxmox VM with /dev/disk/by-id

Passing a physical disk through lets a guest see a real drive rather than a virtual disk. The i12bretro tutorial has exactly five steps; step three contains the DEVICE-ID(S) lookup and qm set command. I retain the identifiers and placeholders while adding the operational warnings.¹

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1. Open the Proxmox web shell

Step 1/5: Log into Proxmox VE at the console or web UI and launch the web shell.

Step 2/5: Note the VM ID that will receive the physical hard disk.

2. Find the disk ID and attach it

Step 3/5: Run the source commands in the shell:

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# list hard disk devices and ids
lsblk |awk 'NR==1{print $0" DEVICE-ID(S)"}NR>1{dev=$1;printf $0" ";system("find /dev/disk/by-id -lname \"*"dev"\" -printf \" %p\"");print "";}'|grep -v -E 'part|lvm'
# copy the /dev/disk/by-id.... for the device to passthrough
# add the disk to the VM, update the VM ID as needed
# usage:
# qm set <%VM ID%> -<%VIRTUAL DEVICE%> <%DEV DISK ID%>
qm set 100 -scsi1 /dev/disk/by-id/scsi-360026b902ad1ae00293167790419d3f2

Copy the correct /dev/disk/by-id/... path for the disk. 100, scsi1, and the serial-like path are source examples; replace the VM ID, virtual device, and real disk ID. Do not substitute /dev/sdX for a stable by-id path when consistent naming across reboots matters.

3. Restart the VM

Step 4/5: Stop the VM and start it again so the new configuration takes effect.

Do not remove the disk or change its host partition while the guest is running. If the host has mounted the filesystem, check ownership and filesystem use before handing it to the VM.

4. Verify inside the guest

Step 5/5: Verify inside the guest OS that the physical disk is connected. Formatting and mounting should then be performed inside the guest according to its operating system and the data on the disk.

Conclusion

The five steps have a clear safety boundary: record the VM ID, find /dev/disk/by-id, run qm set, stop/start the VM, and verify from the guest. Attaching the wrong disk can destroy data; compare model/serial and back up first.

Sources