An upgrade from Windows Server 2008 SP1 to Windows Server 2008 R2 rolls back if the default SAN policy is set to "offline shared"

Consider the following scenario:

• You have a read-only global catalog that is Windows Server 2008 Service Pack 1 (SP1)-based.
• You try to upgrade the computer that hosts the read-only global catalog to Windows Server 2008 R2.

In this scenario, the upgrade rolls back.

This problem occurs when the following conditions are true:

• The storage area network (SAN) policy is enabled on a computer that is running Windows Server 2008 Enterprise Edition or Windows Server 2008 Datacenter Edition.
• The default SAN policy is "offline shared."
• The computer uses multipath I/O (MPIO) disks.
• The Active Directory directory information tree or another important Active Directory component is located on the MPIO disks.

How this happens

1. The default SAN policy is "offline shared." Therefore, all device instances of the MPIO disks are offline.
2. The user sets the MPIO disks online. However, device instances remain offline because the attribute change of the MPIO disk does not affect the device instances.
3. The user starts the upgrade program.
4. The device instances are migrated together with their "offline shared" setting. However, the attributes of the MPIO disks are not migrated.
5. The earlier version of MPIO is uninstalled, and then a later version of MPIO is installed.
6. The upgrade program restarts the computer.
7. The upgrade program creates MPIO disks. However, because no attributes exist for the new disks in the registry, the disks take their attributes from their first device instances. Because all device instances are in an "offline shared" setting, the MPIO disks appear in an "offline shared" setting.
8. The MPIO disks cannot be accessed. Therefore, Active Directory directory information tree or another important Active Directory component that is located on the disks is not found.
9. Upgrade rolls back.

To resolve this problem, use one of the following methods:

• Set all device instances of MPIO disks to "online" before you upgrade by doing the following: .
  1. You can use the diskpart tool to set all device instances of the MPIO disks to "online."
  2. Set the registry "Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\SCSI\<device instance>\Device Parameters\Partmgr\Attributes" to zero.
• Move important components such as the Active Directory directory information tree off the MPIO disks before you start the upgrade.