Just found this very interesting article http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1013109 describing a problem with Windows 2008 and ESX 4 virtual hardware version 7.

In short the article states that you might have the disks go offline in a Windows 2008 VM if you

  • Upgrade virtual hardware from version 4 to 7
  • Installing a new VM with virtual hardware 7

There is two ways to get around this (taken from the VMware KB 103109)


This can be resolved by changing the SAN Automount Policy on the system. See the Microsoft article http://support.microsoft.com/kb/973834 to change the SAN Policy to online.
The SAN policy is defined within the VDS environment of the system and is represented by the following values:
  • VDS_SP_UNKNOWN = 0x0
  • VDS_SP_ONLINE = 0x1
  • VDS_SP_OFFLINE = 0x3
On Windows Server 2008 Enterprise and Windows Server 2008 Datacenter, the default SAN policy is VDS_SP_OFFLINE_SHARED. On all other Windows Server 2008 editions, the default SAN policy is VDS_SP_ONLINE.
To query current SAN policy from the command line, start DISKPART and issue a SAN command:
SAN Policy : Offline Shared


Alternatively, you can set the disk to Online after the hardware version upgrade.
To set the disk to Online:
  1. Log in to your system as an Administrator.
  2. Click Computer Management > Storage > Disk Management.
  3. Right-click the disk and choose Online.