MPIO disk is removed unexpectedly when a PR_IN command fails in a Windows Server 2008 R2 environment

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 website:

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, you must be running Windows Server 2008 R2 or Windows Server 2008 R2 Service Pack 1 (SP1).For more information about how to obtain a Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2

Registry information

After the update is installed, you must create a registry key. To do this, follow these steps.

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 How to back up and restore the registry in Windows

1. Start Registry Editor. To do this, click Start, type regedit in the Start Search box, and then press Enter.
2. Locate and then click the following registry key: 
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\mpio\Parameters
3. On the Edit menu, point to New, and then click DWORD (32 bit) Value. 
4. Type DiskPathCheckEnabled, and then press Enter.
5. On the Edit menu, click Modify.
6. In the Value data box, type 1, and then click OK.
7. Exit Registry Editor.

Notes

• If the DiskPathCheckEnabled key is set to a nonzero value, the MPIO component creates a path recovery worker. This occurs when a PR_IN command fails on all available paths to an MPIO disk.
• To configure the time interval at which the MPIO component starts path recovery attempts, modify the registry key. To do this, follow these steps:
  1. Start Registry Editor. To do this, click Start, type regedit in the Start Search box, and then press Enter.
  2. Locate and then click the following registry key: 
     HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\mpio\Parameters
  3. On the Edit menu, point to New, and then click DWORD (32 bit) Value. 
  4. Type DiskPathCheckInterval, and then press Enter.
  5. On the Edit menu, click Modify.
  6. In the Value data box, type a value to represent a particular number of seconds, and then click OK.
  7. Exit Registry Editor.
• If the DiskPathCheckInterval key is set to 0, or if the key does not exist, the MPIO component uses a default time interval. The default time interval is half of the time that is set in the PDORemovePeriod parameter.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows Server 2008 R2 file information notes

Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, milestone (RTM,SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
  

  Version	Product	Milestone	Service branch
  6.1.760 0.17xxx	Windows Server 2008 R2	RTM	GDR
  6.1.760 0.21xxx	Windows Server 2008 R2	RTM	LDR
  6.1.760 1.17xxx	Windows Server 2008 R2	SP1	GDR
  6.1.760 1.22xxx	Windows Server 2008 R2	SP1	LDR

• GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.
• The MANIFEST files (.manifest) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2" section. MANIFEST files and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x64-based versions of Windows Server 2008 R2

For all supported IA-64-based versions of Windows Server 2008 R2