Found some notes on upgrading VMware 5.1->5.5

See here: http://lonesysadmin.net/2013/10/17/notes-on-upgrading-the-vmware-vcenter-server-appliance-5-1-to-5-5/

Shared storage in VMware workstation

I'm playing with VMware ESXi and one of the features is migrating between hosts that are sharing storage. Obviously I don't have two SANs in my flat, but you can achieve it with VMware workstation for testing purposes by editing the vmx files after creating the storage:

Create an independent, persistent drive as a single file.

shut down your hosts / VMware workstation and edit the appropriate vmx file for each host, here are examples to work from:

# Amend, change these:
scsi1.present = "TRUE"
scsi1.virtualDev = "lsilogic"

scsi1:1.present = "TRUE" 
scsi1:1.fileName = "E:\vmware\sharedds\sharedds1.vmdk" 
scsi1:1.mode = "independent-persistent" 

# Add these:
disk.locking = "false" 
diskLib.dataCacheMaxSize = "0"

Do this on both (or more!) hosts vmx file and you should be able to boot them without locking issues.

Importing other VMs into VMware

In ESXi 5.1 the VMkernel multiextent module is no longer loaded by default, and this module is needed to support virtual disks of hosted formats.

The solution is easy: Manually load the multiextent module by running

   vmkload_mod multiextent