When Raw Device mapping (RDM) used in VMware vSphere the host will take a long time to boot maybe hours. you can follow the next steps to fix this issue:

list all virtual machines with RAW Device Mappings (i tried many script and commands but after hard searching, I found the following script on Pastebin):


Enable SSH (Host Configuration -> Security profile -> Properties -> Start SSH Service)

Start Putty or any other SSH Client login and run the following Command after Changing Device name (naa.600000e00d2800000028097000020000):

Hope this helps.