Symptoms
Consider the following scenario: You are running a Windows Server 2008-based computer that is connected to a storage device over some Microsoft Multipath I/O (MPIO) paths.A Microsoft MPIO Device Specific Module is enabled for these MPIO paths.The storage device is configured as an iSCSI boot device or a Storage Area Network (SAN) boot device.You installand then uninstall Windows Server 2008 Service Pack 2.You have installed hotfix 957316 on the Windows Server 2008-based computer.In this scenario, the computer does not restart if the storage device is a boot device, or you lose access to the device if the device is a data volume.
Note For more information about hotfix 957316, click the following article number to view the article in the Microsoft Knowledge Base:
957316?(http://support.microsoft.com/kb/957316/) Disk I/O errors occur after you restore a failed MPIO path on a Windows Server 2008-based computer
Resolution
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756?(http://support.microsoft.com/kb/322756/) How to back up and restore the registry in Windows
To avoid this problem, install hotfix 967752 before you install Windows Server 2008 Service Pack 2.
Scenario 1
If you have installed Windows Server 2008 Service Pack 2 and then you uninstalled the service pack or if you have not installed Windows Server 2008 Service Pack 2, follow these steps:For the Data VolumeClick Start, click Run, type regedit, and then click OK.In Registry Editor, locate the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEVCopy the entries under the MPDEV subkey, and then enter them under the following subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceListRestart the computer, or disable and then enable host bus adapter (HBA).For the Boot VolumeMask logical unit number (LUN) to another Windows Server 2008-based computer, and then mount the boot volume.Locate the registry (.reg) files.Click Start, click Run, type regedit, and then click OK.In Registry Editor, locate the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEVCopy and paste the registry data in the registry subkey of step 4 under the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceListUnmount the boot volume, and then unmask the LUN from the Windows Server 2008-based computer.Mask the LUN to the Windows Server 2008-based computer for SAN Boot.Restart the computer, and then boot from this LUN.
Scenario 2
If you experience this problem when you prepare for the installation or removal of Windows Server 2008 Service Pack 2, follow these steps:For the Data VolumeClick Start, click Run, type regedit, and then click OK.In Registry Editor, locate the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEVCopy and paste theregistry data in the registry subkey of step 2 into the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceListRestart the computer, or disable and then enable the host bus adapter (HBA).For the Boot VolumeMask logical unit number (LUN) to another Windows Server 2008-based computer and then mount the boot volume.Locate the registry (.reg) files.Click Start, click Run, type regedit, and then click OK.In Registry Editor, locate the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEVCopy and paste the registry data in the registry subkey of step 4 into the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceListUnmount the boot volume, and then unmask the LUN from the Windows Server 2008-based computer.Mask the LUN to the Windows Server 2008-based computer for SAN Boot.Restart the computer, boot from this LUN.
Note When you install Windows Server 2008 SP2, the
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceList registry subkey is backed up to the following file:
%windir%\system32\DsmSupportedDeviceList.txt