Upgrading virtual hardware in ESX 4 may cause Windows 2008 disks to go offline.
Upgrading virtual hardware from version 4 to version 7 may cause Windows 2008 disks to go offline.
Creating a new virtual machine on hardware version 7 may cause Windows 2008 disks to go offline.
Note: The first disk (C: drive) is not affected. Any additional disks may be affected and show marked as Offline within Disk Management.
The default SAN Policy on Windows Enterprise is to not automount SAN disks, resulting in the disks being shown as offline. In comparison for Windows Standard Edition, the SAN Policy is online.
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_SHARED = 0x2
VDS_SP_OFFLINE = 0x3
For more information, see http://msdn.microsoft.com/en-us/library/bb525577(VS.85).aspx.
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.