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
Steps
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/
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
AA31E02A400F11DB9590000C2911D1B8
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
Burnham Forensics 
Thanks 🙂 it works!
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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.
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Did you remember to disable the USBArtibrator service on the new host?
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Hello,
I too have the same issue. I cannot mount the usb drive to another esi host.
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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?
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Same problem here. Device is detected. Partition scheme looks OK. But Datastore not detected
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Great article, works perfect, alot simplier than other guides for same process. Cheers!!
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If you disable the arbitration service it will cause issues trying to connect other disks directly to individual VMs, correct?
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