OffloadWrite is doing PrepareForCriticalIo for the whole VHD in a Windows Server 2012 or Windows Server 2012 R2 Hyper-V host

Applies to: Windows Server 2012 R2 StandardWindows Server 2012 R2 DatacenterWindows Server 2012 Standard More

Symptoms


Consider the following scenario:
  • You have a Hyper-V host that is running Windows Server 2012 or Windows Server 2012 R2.
  • You run a copy for a file in a virtual machine.
  • There is an offload write for Virtual Hard Disk (VHD) in the host.
In this scenario, NTFS in the host would do PrepareForCriticalIo for the whole VHD. This operation may cause the following bad consequences for Cluster Shared Volumes:
  • Redirected I/O may be time-out.
  • Snapshot creation can be stuck until the offloadWrite is complete.
  • Volume dismount will be blocked by inflight I/O. This can cause the Physical Disk Resource to be detected as deadlocked if dismount takes more than 3 minutes, or the cluster node to be bug checked if dismount takes more than 20 minutes.

More Information


Update 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 this specific problem.

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, submit a request to 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: 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 update, you must be running Windows Server 2012 or Windows Server 2012 R2.

Restart information

You must restart the computer after you apply this update.

Update replacement information

This update does not replace any previously released update.

References


For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates

Additional file information

Additional file information for Windows 8 and for Windows Server 2012

Additional files for all supported x86-based versions of Windows 8
File propertyValue
File nameX86_56014e23609081baeb48bda6b3495c99_31bf3856ad364e35_6.2.9200.20886_none_7b25d87a5540ea75.manifest
File versionNot applicable
File size692
Date (UTC)26-Nov-2013
Time (UTC)19:25
File nameX86_microsoft-windows-ntfs_31bf3856ad364e35_6.2.9200.20886_none_a3a7da95076e2568.manifest
File versionNot applicable
File size15,737
Date (UTC)26-Nov-2013
Time (UTC)00:22
Additional files for all supported x64-based versions of Windows 8 and of Windows Server 2012
File propertyValue
File nameAmd64_24b4052843e255cb8cd14f40655a6bb2_31bf3856ad364e35_6.2.9200.20886_none_af9339fcdf921567.manifest
File versionNot applicable
File size696
Date (UTC)26-Nov-2013
Time (UTC)19:27
File nameAmd64_microsoft-windows-ntfs_31bf3856ad364e35_6.2.9200.20886_none_ffc67618bfcb969e.manifest
File versionNot applicable
File size15,743
Date (UTC)26-Nov-2013
Time (UTC)02:15

Additional file information for Windows RT 8.1, Windows 8.1 and Windows Server 2012 R2


Additional files for all supported x86-based versions of Windows 8.1
File propertyValue
File nameX86_dc8c99dba495cb161f11571971ae17d4_31bf3856ad364e35_6.3.9600.16475_none_b49d74ed25032c7c.manifest
File versionNot applicable
File size692
Date (UTC)25-Nov-2013
Time (UTC)20:33
File nameX86_microsoft-windows-ntfs_31bf3856ad364e35_6.3.9600.16475_none_3b1cc060387c295e.manifest
File versionNot applicable
File size16,005
Date (UTC)25-Nov-2013
Time (UTC)00:53
Additional files for all supported x64-based versions of Windows 8.1 and of Windows Server 2012 R2
File propertyValue
File nameAmd64_5a4d7354410a5acc4e9073626a547383_31bf3856ad364e35_6.3.9600.16475_none_948ab61b12c3154e.manifest
File versionNot applicable
File size696
Date (UTC)25-Nov-2013
Time (UTC)20:36
File nameAmd64_microsoft-windows-ntfs_31bf3856ad364e35_6.3.9600.16475_none_973b5be3f0d99a94.manifest
File versionNot applicable
File size16,011
Date (UTC)25-Nov-2013
Time (UTC)02:54
Additional files for Windows RT 8.1
File propertyValue
File nameArm_989d756c9df3d5d52bda7411488a693c_31bf3856ad364e35_6.3.9600.16475_none_f0439903f135fa25.manifest
File versionNot applicable
File size692
Date (UTC)25-Nov-2013
Time (UTC)20:34
File nameArm_microsoft-windows-ntfs_31bf3856ad364e35_6.3.9600.16475_none_3b1f32b838794824.manifest
File versionNot applicable
File size16,005
Date (UTC)25-Nov-2013
Time (UTC)00:31