Some I/O requests to a storage device fail on a fault-tolerant system that is running Windows Server 2008 or Windows Server 2008 R2 when you perform a surprise removal of one path to the storage device

Article ID: 2406705 - View products that this article applies to.
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SYMPTOMS

Consider the following scenario:
  • You connect a computer that is running Windows Server 2008 or Windows Server 2008 R2 to a storage device.
  • You configure Microsoft Multipath I/O (MPIO) and Microsoft Device Specific Module (MSDSM) to control the storage device.
  • You perform a surprise removal of one path to the storage device. This behavior starts the failover operation to the remaining path.
In this scenario, the MSDSM reports that it did not return a valid path even though there is at least one valid path. Therefore, I/O requests to the logical unit number (LUN) are not switched to the other path, and the storage connectivity is not fully functional.

Additionally, the following System event log entries are reported:

ID: 32
Level: Error Provider: mpio
Machine: <computer name>
Message: Microsoft DSM failed to return a Path to \Device\<MPIO disk>.


ID: 16
Level: Error
Provider: mpio
Machine: <computer name>
Message: A fail-over on \Device\<MPIO disk> occurred.


Without a valid path, I/O to the MPIO disk fails, and the MPIO disk is torn down. A dialog box that indicates that delayed writes failed is displayed, and the following System event log entry is reported:

ID: 26 Level: Information
Source: Application Popup
Machine : <computer name>
Message: Application popup: Windows - Delayed Write Failed

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CAUSE

This issue occurs because the Microsoft Multipath I/O (MPIO) driver (mpio.sys) incorrectly starts two failover requests for the same failed path.

A race condition in the MPIO failover handling leads to multiple attempts at removing the same failed path. When I/O fails on one device and starts the failover on that device, another device that is in the same failover group (for example, has the same Path ID) also fails over. If there is no failed I/O on the second device for the failover, the state of the second device goes straight from NORMAL to DEGRADED. The reason why the state goes from NORMAL to DEGRADED is that the device does not complete FAILOVER/WAIT1/WAIT2 states, and the state does not wait for the I/O to be completed on the device. The issue occurs when an I/O is completed after the failover is finished.
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RESOLUTION

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
(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 one of the following operating systems:
  • Windows Server 2008
  • Windows Server 2008 Service Pack 2 (SP2)
  • Windows Server 2008 R2
  • Windows Server 2008 R2 Service Pack 1 (SP1)
For more information about how to obtain a Windows Server 2008 service pack, click the following article number to view the article in the Microsoft Knowledge Base:
968849
(http://support.microsoft.com/kb/968849/ )
How to obtain the latest service pack for Windows Server 2008
For more information about how to obtain a Windows 7 or a Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:
976932
(http://support.microsoft.com/kb/976932/ )
Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2

Registry information

To use the hotfix, you do not have to change the registry.

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 file information notes
Important Windows Vista hotfixes and Windows Server 2008 hotfixes are included in the same packages. However, only "Windows Vista" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows Vista" 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, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.
    Collapse this tableExpand this table
    VersionProductSR_LevelService branch
    6.0.600 1 . 22xxxWindows Server 2008SP1LDR
    6.0.600 2 . 22xxxWindows Server 2008SP2LDR
  • Service Pack 1 is integrated into the release version of Windows Server 2008.
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008" section. MUM files and 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 x86-based versions of Windows Server 2008
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File nameFile versionFile sizeDateTimePlatform
Mpio.sys6.0.6001.22876105,87212-Mar-201116:27x86
Mpio.sys6.0.6002.22610106,38412-Mar-201116:27x86
For all supported x64-based versions of Windows Server 2008
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Mpio.sys6.0.6001.22876129,93612-Mar-201116:22x64
Mpio.sys6.0.6002.22610130,44812-Mar-201116:22x64
For all supported IA-64-based versions of Windows Server 2008
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Mpio.sys6.0.6001.22876289,16812-Mar-201116:19IA-64
Mpio.sys6.0.6002.22610290,19212-Mar-201116:19IA-64
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:
    Collapse this tableExpand this table
    VersionProductMilestoneService branch
    6.1.760 0.20xxxWindows Server 2008 R2RTMLDR
    6.1.760 1.21xxxWindows Server 2008 R2SP1LDR
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2" section. MUM and 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
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Mpio.sys6.1.7600.20959156,54404-May-201105:18x64
Mpio.sys6.1.7601.21720156,54404-May-201105:29x64
For all supported IA-64-based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Mpio.sys6.1.7600.20959353,66404-May-201104:19IA-64
Mpio.sys6.1.7601.21720353,15204-May-201104:19IA-64
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STATUS

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684
(http://support.microsoft.com/kb/824684/ )
Description of the standard terminology that is used to describe Microsoft software updates

Additional file information

Additional file information for Windows Server 2008

Additional files for all supported x86-based versions of Windows Server 2008
Collapse this tableExpand this table
File nameUpdate.mum
File versionNot Applicable
File size3,078
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
File nameX86_mpio.inf_31bf3856ad364e35_6.0.6001.22876_none_1d76d8f8a8a526ea.manifest
File versionNot Applicable
File size1,659
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
File nameX86_mpio.inf_31bf3856ad364e35_6.0.6002.22611_none_1f992adca59f52dc.manifest
File versionNot Applicable
File size1,659
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
Additional files for all supported x64-based versions of Windows Server 2008
Collapse this tableExpand this table
File nameAmd64_mpio.inf_31bf3856ad364e35_6.0.6001.22876_none_7995747c61029820.manifest
File versionNot Applicable
File size1,661
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
File nameAmd64_mpio.inf_31bf3856ad364e35_6.0.6002.22610_none_7bb6c6165dfdaabb.manifest
File versionNot Applicable
File size1,661
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size3,102
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
Additional files for all supported IA-64-based versions of Windows Server 2008
Collapse this tableExpand this table
File nameIa64_mpio.inf_31bf3856ad364e35_6.0.6001.22876_none_1d787ceea8a32fe6.manifest
File versionNot Applicable
File size1,660
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
File nameIa64_mpio.inf_31bf3856ad364e35_6.0.6002.22610_none_1f99ce88a59e4281.manifest
File versionNot Applicable
File size1,660
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size2,257
Date (UTC)12-Mar-2011
Time (UTC)16:33
PlatformNot Applicable

Additional file information for Windows Server 2008 R2

Additional files for all supported x64-based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameAmd64_mpio.inf_31bf3856ad364e35_6.1.7600.20959_none_79d5e577c206e92b.manifest
File versionNot Applicable
File size2,073
Date (UTC)04-May-2011
Time (UTC)06:02
PlatformNot Applicable
File nameAmd64_mpio.inf_31bf3856ad364e35_6.1.7601.21720_none_7bd3afa7bf1d1d35.manifest
File versionNot Applicable
File size2,073
Date (UTC)04-May-2011
Time (UTC)05:56
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size3,170
Date (UTC)04-May-2011
Time (UTC)08:17
PlatformNot Applicable
Additional files for all supported IA-64-based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameIa64_mpio.inf_31bf3856ad364e35_6.1.7600.20959_none_1db8edea09a780f1.manifest
File versionNot Applicable
File size2,071
Date (UTC)04-May-2011
Time (UTC)05:58
PlatformNot Applicable
File nameIa64_mpio.inf_31bf3856ad364e35_6.1.7601.21720_none_1fb6b81a06bdb4fb.manifest
File versionNot Applicable
File size2,071
Date (UTC)04-May-2011
Time (UTC)05:46
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size1,933
Date (UTC)04-May-2011
Time (UTC)08:17
PlatformNot Applicable
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Properties

Article ID: 2406705 - Last Review: June 15, 2011 - Revision: 4.0
APPLIES TO
  • Windows Server 2008 R2 Datacenter
  • Windows Server 2008 R2 Enterprise
  • Windows Server 2008 R2 for Itanium-Based Systems
  • Windows Server 2008 R2 Foundation
  • Windows Server 2008 R2 Standard
  • Windows Web Server 2008 R2
  • Windows HPC Server 2008 R2
  • Windows Server 2008 Datacenter
  • Windows Server 2008 Datacenter without Hyper-V
  • Windows Server 2008 Enterprise
  • Windows Server 2008 Enterprise without Hyper-V
  • Windows Server 2008 for Itanium-Based Systems
  • Windows Server 2008 Foundation
  • Windows Server 2008 Standard
  • Windows Server 2008 Standard without Hyper-V
Keywords: 
kbautohotfix kbqfe kbhotfixserver kbfix kbsurveynew kbexpertiseadvanced KB2406705
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