Manually attach USB Device as a VMFS Datastore in ESXI

I recently attempted to upgrade the storage on my home server while looking for the means to preserve the data on my soon-to-be old drive. One solution I attempted was to attach an external USB drive and to temporarily migrate files and VMs over until I could replace the it. Upon trying this, however, I soon realized ESXI was unable to recognize my Western Digital 1TB External Drive.

Below are some steps on how to manually add and format a USB device as a VMFS Datastore to ESXI utilizing ESXI’s shell.

Important Information

  • This was tested on ESXI 6.7.0
  • As of now, ESXI does NOT support USB devices over 2TB


Temporarily enable SSH access to your ESXI host

Remotely access ESXI using SSH to access ESXI’s shell

Stop the USB arbitrator service

/etc/init.d/usbarbitrator stop

Plug in and look for your desired USB device

ls /dev/disks/
If you squint reaaaaaally hard… 🙂

Write a GPT label to your USB device using it’s ID:

Ex: t10.WD______MyPassport_0740wx51A1309457____

partedUtil mklabel /dev/disks/<deviceID> gpt

To manually create a new partition of anything, you need to know the start and end sector as well as the GUID of the desired file system.

Calculate (yes, math) the end sector for your new partition from the resulting numbers from the following command:

partedUtil getptbl /dev/disks/<deviceID>

Example Calculation: 121597 * 255 * 63 -1 = 1953455804

Start sector will ALWAYS be 2048, and the VMFS GUID is

Create VMFS partition using the number you calculated (end sector), the start sector (2048) and the VMFS GUID

partedUtil setptbl /dev/disks/<deviceID> gpt "1 2048 <endSector> AA31E02A400F11DB9590000C2911D1B8 0"

Format your new partition with VMFS6

vmkfstools -C vmfs6 -S External-Storage /dev/disks/<deviceID>:1 

NOTE: Replace “External-Storage” in the above command with whatever you wish your Datastore name to be.

Go back to ESXI and navigate to the Storage tab. You should see your new Datastore enjoying its new home.

Re-disable SSH access to your ESXI host


8 thoughts on “Manually attach USB Device as a VMFS Datastore in ESXI

  1. hi,

    how can i mount this datastore to new esxi host?

    we are using ESXi free version and we build a new esxi host.

    i copied the vmdk files to the external hdd from old esxi host. but when i mount this ext hdd to new esxi host it is not listed as datastore rather just a drive but unable to browse the content.


  2. Hello,
    Ok. Now that the drive is formatted properly, I wanted to move the drive to another ESXi host to mount the datastore. The new ESXi host can see the device but can not mount the USB drive. Any suggestions?


  3. If you disable the arbitration service it will cause issues trying to connect other disks directly to individual VMs, correct?


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