TrueNAS Scale VM: Configuring Virtual Disk Serials

Overview

This guide explains how to assign custom serial numbers to Proxmox virtual disks.

This is required for TrueNAS Scale to correctly identify disks and form ZFS pools in a virtualized environment.

[!WARNING] Test Labs Only Never use virtual disks for production TrueNAS deployments. It prevents ZFS from accessing SMART data and increases data loss risk.

Prerequisites

A running PVE node.
A created TrueNAS Scale VM on your PVE node.
Basic shell knowledge.

Steps

Step 1: Locate VM Config

Open an SSH connection to your Proxmox node and identify your TrueNAS VM ID (e.g., 100).

Step 2: Add Serial Numbers

Edit the QEMU server configuration file for your VM:

vi /etc/pve/qemu-server/${TRUENAS_VMID}.conf

Locate the lines defining your hard disks (usually starting with scsi). Append a unique serial parameter ,serial=XXXX to the end of each disk line.

Example Configuration:

# Before
scsi1: local-lvm:vm-100-disk-1,discard=on,iothread=1,size=16G,ssd=1
scsi2: local-lvm:vm-100-disk-2,discard=on,iothread=1,size=16G,ssd=1

# After (Ensure every serial string is unique)
scsi1: local-lvm:vm-100-disk-1,discard=on,iothread=1,size=16G,ssd=1,serial=TRUENAS-01
scsi2: local-lvm:vm-100-disk-2,discard=on,iothread=1,size=16G,ssd=1,serial=TRUENAS-02

Step 3: Apply Changes

For these hardware changes to register, you must fully stop and start the VM (a reboot is not sufficient).

qm stop ${TRUENAS_VMID}
qm start ${TRUENAS_VMID}

Verification

Open the Shell inside your running TrueNAS VM and run:

lsblk -o NAME,SERIAL,SIZE

Expected Output:

NAME   SERIAL      SIZE
sda    TRUENAS-01  16G
sdb    TRUENAS-02  16G

Troubleshooting

"Disk Serial" or Multipath Errors

Problem: TrueNAS complains about duplicate disks or fails to create the pool. Solution: You likely pasted the same serial number for multiple disks. Re-open the .conf file and ensure every serial=... string is unique.

Created: 2026-01-14

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