VMWare Raw Device Mapping for local storage (if greyed out)

If you have the issue that you are not able to (re-)attach a raw device/hard drive to a virtual machine, this might be due to an unsupported or internal controller. Internal controllers have this functionality disabled by default. "Local storage devices often do not support VPD page 0x83, and thus cannot be used for Raw Device Mappings (RDMs). The content of page 0x83 is used as a unique identifier for the device."

You can find more in an VMWare article here: https://kb.vmware.com/s/article/1010244

1. Identify the disk name (all from console).

# ls -l /vmfs/devices/disks | cat t10

Look for the hdd identifier like t10.F405E46494C4540046F4123456ABCDEFG41707D203F45765

2. Enable the disk.

# vmkfstools -z /vmfs/devices/disks/diskname /vmfs/volumes/datastorename/vmfolder/vmname.vmdk

Note that datastorename/vmfolder must be an existing datastore and VMWare.

Now you can add the disk as "Existing virtual disk".

Full documentation can be found here: https://kb.vmware.com/s/article/1017530

Good Luck.