In newer version of VMWare (example version 5), you can only Raw Disk Mapping (RDM) a SAN storage, and not the local storage or harddisk. However there is a trick to do this:
- Log in as root through ssh or just go to the console terminal (refer Enable SSH at ESX Host)
- Now you need to find out the physical disk path that you will be doing RDM, using either the following commands:
esxcfg-mpath -lls -al /vmfs/devices/disks
- Then you need to map the disk as a virtual disk using following command:
vmkfstools -r /vmfs/devices/disks/<physical disk path> /vmfs/volumes/<vmfs datastore name>/<folder name>/<virtual disk name>.vmdk
Now you can view the physical disk as virtual disk and add it to VM.
Reference: Add Local Storage (e.g. a SATA disk) as a Raw Disk Mapping (RDM) or Mapped RAW LUN to a virtual machine hosted on ESXi