Applications or services that call the CVdsService::Reenumerate function may receive incorrect results in Windows Server 2008 and in Windows Vista SP1

Article ID: 950851 – Last Review: January 20, 2009 – Revision: 1.0

Applications or services that call the CVdsService::Reenumerate function may receive incorrect results in Windows Server 2008 and in Windows Vista SP1

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SYMPTOMS

In Windows Server 2008 and in Windows Vista Service Pack 1 (SP1), applications or services that call the CVdsService::Reenumerate function to rescan logical unit number (LUN) objects may receive incorrect results.

For example, an application breaks a LUN object mirror, masks one plex, and then unmasks the plex to another computer. After the application performs the unmasking action, the application calls the CVdsService::Reenumerate function to rescan LUN objects. Because of this issue, the plex does not appear on the expected computer, and an exception occurs.

CAUSE

If the storport and SCSIport drivers receive two LUN object rescan calls within 30 seconds, the drivers skip the second rescan call. When the rescan call is skipped, the problem that is mentioned in the Symptoms section may occur.

RESOLUTION

To resolve this problem, install the following hotfix. This hotfix adds a delay of 45 seconds in the CVdsService::Reenumerate function to make sure that each re-enumeration call triggers a storage rescan.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a Hotfix download available section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support (http://support.microsoft.com/contactus/?ws=support)

Note The Hotfix download available form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix on a Windows Server 2008-based computer, no prerequisites are required.

To apply this hotfix on a Windows Vista-based computer, you must have Windows Vista SP1 installed. For more information about Windows Vista service packs, click the following article number to view the article in the Microsoft Knowledge Base:

935791  (/Feedback.aspx?kbNumber=935791/ ) How to obtain the latest Windows Vista service pack

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista and Windows Server 2008 file information notes

The MANIFEST (.manifest) files and MUM (.mum) files that are installed for each environment are listed separately. MUM and MANIFEST files and their associated security catalog (.cat) files are critical to maintaining the state of the updated component. The security catalog files are signed with a Microsoft digital signature. The attributes of these files are not listed.

All supported x86-based versions of Windows Server 2008 and of Windows Vista
Collapse this tableExpand this table
File name File version File size Date Time Platform
Vds.exe 6.0.6001.22240 382,976 09-Aug-2008 03:30 x86
Vdsldr.exe 6.0.6001.22240 19,968 09-Aug-2008 03:30 x86
Vdsutil.dll 6.0.6001.22240 128,000 09-Aug-2008 03:30 x86
Vds_ps.dll 6.0.6001.22240 37,888 09-Aug-2008 03:30 x86
All supported x64-based versions of Windows Server 2008 and of Windows Vista
Collapse this tableExpand this table
File name File version File size Date Time Platform Service branch
Vds.exe 6.0.6001.22240 453,120 09-Aug-2008 04:07 x64 Not applicable
Vdsldr.exe 6.0.6001.22240 22,528 09-Aug-2008 04:07 x64 Not applicable
Vdsutil.dll 6.0.6001.22240 157,696 09-Aug-2008 04:08 x64 Not applicable
Vds_ps.dll 6.0.6001.22240 97,280 09-Aug-2008 04:08 x64 Not applicable
Vdsldr.exe 6.0.6001.22240 19,968 09-Aug-2008 03:30 x86 WOW
Vdsutil.dll 6.0.6001.22240 128,000 09-Aug-2008 03:30 x86 WOW
Vds_ps.dll 6.0.6001.22240 37,888 09-Aug-2008 03:30 x86 WOW
All supported IA-64-based versions of Windows Server 2008
Collapse this tableExpand this table
File name File version File size Date Time Platform Service branch
Vds.exe 6.0.6001.22240 846,336 09-Aug-2008 03:51 IA-64 Not applicable
Vdsldr.exe 6.0.6001.22240 49,152 09-Aug-2008 03:51 IA-64 Not applicable
Vdsutil.dll 6.0.6001.22240 338,432 09-Aug-2008 04:02 IA-64 Not applicable
Vds_ps.dll 6.0.6001.22240 109,056 09-Aug-2008 04:02 IA-64 Not applicable
Vdsldr.exe 6.0.6001.22240 19,968 09-Aug-2008 03:30 x86 WOW
Vdsutil.dll 6.0.6001.22240 128,000 09-Aug-2008 03:30 x86 WOW
Vds_ps.dll 6.0.6001.22240 37,888 09-Aug-2008 03:30 x86 WOW

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the Applies to section.

MORE INFORMATION

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  (/Feedback.aspx?kbNumber=322756/ ) How to back up and restore the registry in Windows

Some applications that require Virtual Disk Service (VDS) calls to be completed quickly may be severely affected by this 45-second delay. To work around this issue, you can modify the appropriate registry entry to disable the delay. To do this, follow these steps:

  1. Click Start, type regedit in the Start search box, and then press ENTER.

    If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation.

  2. Locate and then click the following registry subkey:
    HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services VDS
  3. On the Edit menu, point to New, and then click DWORD (32-bit) Value.
  4. Type DisableReenumDelay, and then press ENTER.
  5. Right-click DisableReenumDelay, and then click Modify.
  6. In the Value data box, type 1, and then click OK.
  7. Exit Registry Editor.

The value of the registry entry is read when the service is loaded. Therefore, you must restart VDS to make the value active.

You cannot disable the delay on a per-application basis. You can disable the delay only system-wide. After you disable the delay, disk changes may not be found by re-enumerate calls. Therefore, applications that rely on VDS notifications to find new disks may not receive these notifications. Some applications may not work correctly if they do not receive notifications of disk arrivals or of disk removals. Therefore, if this is a concern for you, make sure that you do not disable the delay.

If an application can recognize the disks that are supposed to be available, the application may be able to work around these lost notifications by verifying whether a disk is detected. For example, when an application masks or unmasks a LUN object, the application may recognize the disks that should be available. Therefore, we recommend that you use this hotfix only when the following conditions are true:

  • The applications that use VDS can work around the lost notifications.
  • No other applications use VDS to find disk arrivals and disk removals.

For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:

949002  (/Feedback.aspx?kbNumber=949002/ ) A 45-second delay occurs when a Windows Server 2003-based computer runs disk re-enumeration operations after you install hotfix 935949 or a later version of Virtual Disk Service (Vds.exe)
935949  (/Feedback.aspx?kbNumber=935949/ ) The Virtual Disk Service (VDS) in Windows Server 2003 does not return port-specific identifiers for a storage device

For more information about LUN objects, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn.microsoft.com/en-us/library/aa383041(VS.85).aspx (http://msdn.microsoft.com/en-us/library/aa383041(VS.85).aspx)

Additional file information for Windows Server 2008 and for Windows Vista

Additional files for all supported x86-based versions of Windows Server 2008 and of Windows Vista
Collapse this tableExpand this table
File name File version File size Date Time Platform
Package_for_kb950851_client_1~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,367 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_client~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,431 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_sc_0~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,421 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_sc~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,423 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_server_0~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,425 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_server~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,431 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_winpesrv_0~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,422 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_winpesrv~31bf3856ad364e35~x86~~6.0.6.0.mum Not applicable 1,429 09-Aug-2008 11:55 Not applicable
X86_microsoft-windows-virtualdiskservice_31bf3856ad364e35_6.0.6001.22240_none_6b4931a113eca8ee.manifest Not applicable 99,984 09-Aug-2008 04:14 Not applicable
Additional files for all supported x64-based versions of Windows Server 2008 and of Windows Vista
Collapse this tableExpand this table
File name File version File size Date Time Platform
Amd64_microsoft-windows-virtualdiskservice_31bf3856ad364e35_6.0.6001.22240_none_c767cd24cc4a1a24.manifest Not applicable 100,048 09-Aug-2008 04:53 Not applicable
Package_for_kb950851_client_1~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,375 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_client~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,439 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_sc_0~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,429 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_sc~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,431 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_server_0~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,433 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_server~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,439 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_winpesrv_0~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,430 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_winpesrv~31bf3856ad364e35~amd64~~6.0.6.0.mum Not applicable 1,437 09-Aug-2008 11:55 Not applicable
Wow64_microsoft-windows-virtualdiskservice_31bf3856ad364e35_6.0.6001.22240_none_d1bc777700aadc1f.manifest Not applicable 98,699 09-Aug-2008 03:55 Not applicable
Additional files for all supported IA-64-based versions of Windows Server 2008
Collapse this tableExpand this table
File name File version File size Date Time Platform
Ia64_microsoft-windows-virtualdiskservice_31bf3856ad364e35_6.0.6001.22240_none_6b4ad59713eab1ea.manifest Not applicable 100,012 09-Aug-2008 04:52 Not applicable
Package_for_kb950851_sc_0~31bf3856ad364e35~ia64~~6.0.6.0.mum Not applicable 1,425 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_sc~31bf3856ad364e35~ia64~~6.0.6.0.mum Not applicable 1,426 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_server_0~31bf3856ad364e35~ia64~~6.0.6.0.mum Not applicable 1,429 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_server~31bf3856ad364e35~ia64~~6.0.6.0.mum Not applicable 1,434 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_winpesrv_0~31bf3856ad364e35~ia64~~6.0.6.0.mum Not applicable 1,426 09-Aug-2008 11:55 Not applicable
Package_for_kb950851_winpesrv~31bf3856ad364e35~ia64~~6.0.6.0.mum Not applicable 1,433 09-Aug-2008 11:55 Not applicable
Wow64_microsoft-windows-virtualdiskservice_31bf3856ad364e35_6.0.6001.22240_none_d1bc777700aadc1f.manifest Not applicable 98,699 09-Aug-2008 03:55 Not applicable

APPLIES TO
  • Windows Server 2008 Standard
  • Windows Server 2008 Enterprise
  • Windows Server 2008 Datacenter
  • Windows Server 2008 Standard without Hyper-V
  • Windows Server 2008 Enterprise without Hyper-V
  • Windows Server 2008 Datacenter without Hyper-V
  • Windows Server 2008 for Itanium-Based Systems
  • Windows Vista Business
  • Windows Vista Enterprise
  • Windows Vista Home Basic
  • Windows Vista Home Premium
  • Windows Vista Ultimate
  • Windows Vista Business 64-bit Edition
  • Windows Vista Enterprise 64-bit Edition
  • Windows Vista Home Basic 64-bit Edition
  • Windows Vista Home Premium 64-bit Edition
  • Windows Vista Ultimate 64-bit Edition
Keywords: 
kbautohotfix kbexpertiseinter kbfix kbbug kbsurveynew kbqfe kbhotfixserver KB950851

 

Microsoft Knowledge Base Article

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