Recently at work I had to migrate a physical server to a VMWare-instance. First I made a dump of the live (!!!) system using dd.
dd if=/dev/sda
| ssh [email protected]
'cat - > /opt/vmware/oldserver/oldhd.dd'
When this was done, I had to create a VMDK-file, otherwise VMWare-server doesn't understand (there is no support to add 'raw' images to an instance. You can create a VMDK-file using dd2vmdk 
After this, I added the virtual-disk to the virtual instance. 
So I powerup the vmware-instance... and guess what... A Kernel Panic occurs 
But... no panic... I started digging into the initial ramdisk. And I found that the SATA-module, which is required for booting a VMWare-SCSI disk, is not available in the initrd 
So, I had two options:
- Create a new ramdisk with the right modules;
- Change the type of the virtual disk into IDE.
I choose for the second option, the main VMDK-file is a plaintext file and all you have to do is change the entry:
ddb.adapterType = "lsilogic"
into
ddb.adapterType = "ide"
And after powerup the system again... It worked
