TrueNAS incorrectly pulls rotation speed of a virtual disk under VMWare Workstation

TrueNAS General
1

In the WebUI, as well as when running midclt call disk.query | jq, one of the virtual disks passed to TrueNAS Scale under VMWare Workstation shows rotation speed of 15K:

  {
    "identifier": "{serial_lunid}6000c29da1ec0401b00a68b305c6b183_6000c29da1ec0401",
    "name": "sdb",
    "subsystem": "scsi",
    "number": 2064,
    "serial": "6000c29da1ec0401b00a68b305c6b183",
    "lunid": "6000c29da1ec0401",
    "size": 21474836480,
    "description": "",
    "transfermode": "Auto",
    "hddstandby": "ALWAYS ON",
    "advpowermgmt": "DISABLED",
    "expiretime": null,
    "model": "VMware_Virtual_S",
    "rotationrate": 15000,
    "type": "HDD",
    "zfs_guid": "8844258940006280448",
    "bus": "SCSI",
    "devname": "sdb",
    "enclosure": null,
    "pool": null
  },

This appears to happen on one of 7 SCSI virtual disks. Other disks correctly show null for rotation rate:

  {
    "identifier": "{serial_lunid}6000c295f164cd044218b634749f2918_6000c295f164cd04",
    "name": "sdd",
    "subsystem": "scsi",
    "number": 2096,
    "serial": "6000c295f164cd044218b634749f2918",
    "lunid": "6000c295f164cd04",
    "size": 21474836480,
    "description": "",
    "transfermode": "Auto",
    "hddstandby": "ALWAYS ON",
    "advpowermgmt": "DISABLED",
    "expiretime": null,
    "model": "VMware_Virtual_S",
    "rotationrate": null,
    "type": "HDD",
    "zfs_guid": "10183660113133072398",
    "bus": "SCSI",
    "devname": "sdd",
    "enclosure": null,
    "pool": null
  },

Oddly, the output of smartctl shows rotation rate too:

truenas_admin@truenas[~]$ sudo smartctl -a /dev/sdb
[sudo] password for truenas_admin: 
smartctl 7.4 2023-08-01 r5530 [x86_64-linux-6.12.33-production+truenas] (local build)
Copyright (C) 2002-23, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Vendor:               VMware,
Product:              VMware Virtual S
Revision:             1.0
User Capacity:        21,474,836,480 bytes [21.4 GB]
Logical block size:   512 bytes
Rotation Rate:        15000 rpm
Logical Unit id:      0x6000c29da1ec0401b00a68b305c6b183
Serial number:        6000c29da1ec0401b00a68b305c6b183
Device type:          disk
Local Time is:        Mon Mar 23 09:55:19 2026 PDT
SMART support is:     Unavailable - device lacks SMART capability.

=== START OF READ SMART DATA SECTION ===
Current Drive Temperature:     0 C
Drive Trip Temperature:        0 C

Error Counter logging not supported

Device does not support Self Test logging

Is this a bug in VMWare Workstation, a bug in TN, a bug upstream, or a skill issue? I have never encountered this behavior in the past.

2

Virtual devices have nothing to do with the actual hardware that is underneath. Its an emulation.
You can emulate 12 cpu cores on a 4 core CPU.

That beeing said, if you value your data, dont use virtual devices for Truenas ( other than the boot device). As for the hypervisor. Proxmox and esxi can be made to work reliably ( with caveats). But yours is IMO a type 2 hypervisor and these are not recommended at all.

3

I used ESXi v7 and v8 to run FreeNAS, TrueNAS Core, and TrueNAS Scale without any issues at all. I don’t recall but I thought you could tell the emulation the RPM and other values in ESXi, but I no longer use ESXi at the time. I may go back to it, not sure. I’m giving Scale on bare metal a try for at least 1 year, less if I run into problems.

4

I am trying to evaluate TN in VMWare Workstation. I think that it’s a fair use case. While I do have the hardware to test TN on, some configurations/tests are simply easier and quicker to run in a VM.

1 Like
5

Thats perfectly fine.

6

Update: I booted into Parted Magic and it too shows the 15K rotation speed for one of the virtual disks. I am going to investigate this outside TN. Thanks everyone for your input.

1 Like
7

It’s possible that the device isn’t set with having “SSD Emulation” enabled in either the .vmx or .vmdk descriptors for it specifically, and the others are.

8

The weird thing is that all the virtual disks were created exactly the same way through the Workstation GUI. I am going to have a dig in the .vmx first.

9

Love to hear the results

10

I took a look and I did not see anything unusual in the vmx file.