We are used to the VMware virtual disk format (vmdk-files)
This VMDK-files can be attached to a VM so that the guestOS perceives them as:
\u2013 IDE-device
\u2013 SCSI-device
\u2013 SATA-device
\u2013 NVME-device
Until today I was not aware of the fact that there is one more option:
\u2013 USB-device<\/b>
This feature is not exposed in the GUI but using it is quite easy and straight forward.
To define an existing VMDK as USB-device you have to edit the vmx-file.
First of all make sure that you have this line:
ehci.present = \u201cTRUE\u201d
You need this line as a main switch for USB 2 ports.
You should also see a line like
ehci.pciSlotNumber = \u201c35\u201d
Do not edit this line \u2013 instead simply delete it if you want to reset the port.
If you assign a \u201cbad\u201d port you will get obscure follow-up problems \u2013 so don\u2019t do it.
Now to assign a VMDK as USB-device set this parameters:<\/p>\n
ehci:0.present = \u201cTRUE\u201d
ehci:0.deviceType = \u201cdisk\u201d
ehci:0.fileName = \u201cusb-vmdk.vmdk\u201d<\/p>\n
ehci:1.present = \u201cTRUE\u201d
ehci:1.deviceType = \u201cdisk\u201d
ehci:1.fileName = \u201cusb2-vmdk.vmdk\u201d<\/p>\n
Using this appears to be possible for more than one VMDK \u2013 so it maybe possible that the full range from ehci0 \u2013 ehci5 is allowed.
This is just a first guess \u2013 I need to do more research here \u2026.<\/p>\n
I said that this feature is not exposed in the GUI \u2013 that is not entirely correct. Inside a guest both vmdks appear like this: (using my Linux-LiveCD with Ubuntu 14)<\/p>\n Anyway \u2013 even at the moment I would call this an extremly useful \u201cnew\u201d feature.<\/p>\n 1. for all those guys that develope USB-bootable tools<\/p>\n If the USB-vmdks are created with the monolithicFlat VMDK-format the USB-images can be easily transferred to real USB-devices with a simple dd-command.<\/p>\n 2. for all users who are looking for a way to assign VMDKS as \u201coptional\u201d<\/p>\n A USB-vmdk is allowed to be temporarily unavailable !!! 3. for all users that missed the option to assign single-partition images as a VMDK.<\/p>\n All other options to assign VMDKs usually require a partitioned image including a valid MBR or GPT.<\/p>\n","protected":false},"excerpt":{"rendered":" As anyone who has tried to use a USB licensing key or test USB devices in a VMware\/vSphere cluster environment knows that using a USB can be problematic. You may have dozens or hundreds of guests on multiple hosts in you data center\/cluster; and trying to map a USB port to just one VM gets … Continue reading “Virtual USB-disks on VMware Guests”<\/span><\/a><\/p>\n","protected":false},"author":587,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[277,181,182],"tags":[],"class_list":["post-1571","post","type-post","status-publish","format-standard","hentry","category-usb","category-vmware","category-vsphere"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t
Once you created the required vmx-parameters and start the VM you will see the disks appear in the list of removable devices:![\"clip_image001\"](\"https:\/\/mikemartinezonline.com\/blog\/wp-content\/uploads\/2019\/12\/clip_image001.png\" "\\"clip_image001\\"")
<\/a><\/p>\n![\"clip_image002\"](\"https:\/\/mikemartinezonline.com\/blog\/wp-content\/uploads\/2019\/12\/clip_image002.png\" "\\"clip_image002\\"")
<\/a>
During my experiments I noticed that the USB-vmdks may appear in a write protected mode.
At the moment I cant claim to have completely understood in which constellation the vmdks are write-protected.
This will require further research \u2026.<\/p>\n
All other options to assign VMDKs will fail if the file is not present.
With USB-vmdks the VM will start even if the file is not available.
This will open new paths to acchieve obscure constellations that were impossible until now.<\/p>\n