System fails back to a host copy instead of an array copy or storages go down after LUN reset in Windows Server 2012 R2

Gilt für: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 StandardWindows Server 2012 R2 Essentials

This article describes issues in which a storage system fails back to a host copy instead of an array copy or storage systems go down after a LUN reset in Windows Server 2012 R2. An update is available to fix these issues. Before you install this update, see the Prerequisites section.

Issues that are fixed in this update

Issue 1

When you run a replication between remote sites on EMC Symmetrix storage arrays, the system fails back to a host copy instead of an array copy.

Issue 2

Storage systems, such as Scale-Out File Server, go down after you run a logical unit number (LUN) reset.

Cause for issue 1

Windows Offloaded Data Transfer (ODX, also known as copy offload) operations have a four-second limit, and this issue occurs because ODX times out.

Note After you install the update that is described in this article, you have to manually add a new registry entry that names CopyOffloadMaxTargetDuration by the following steps. The value of this CopyOffloadMaxTargetDuration registry entry indicates the time in seconds before an ODX will time out. If this value is not present, the default time-out of four seconds is used.

Important Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restorationin case problems occur.
  1. In Registry Editor, locate and then select the following registry subkey:
  2. Press and hold (or right-click) Configuration, select New, and then select DWORD (32-bit) Value.
  3. Name the new registry entry as CopyOffloadMaxTargetDuration.
  4. Exit Registry Editor.

Cause for issue 2

This issue occurs because the LSI driver doesn't communicate correctly with the other nodes and the state doesn’t get synchronized correctly.

How to get this update

Important If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Method 1: Windows Update

This update is provided as a Recommended update on Windows Update. For more information on how to run Windows Update, see How to get an update through Windows Update.

Method 2: Microsoft Download Center

The following files are available for download from the Microsoft Download Center:

Operating systemUpdate
All supported x86-based versions of Windows 8.1Download Download the package now.
All supported x64-based versions of Windows 8.1 Download Download the package now.
All supported x64-based versions of Windows Server 2012 R2Download Download the package now.
Note The update for Windows RT 8.1 can be downloaded only from Windows Update.

For more information about how to download Microsoft support files, select the following article number to view the article in the Microsoft Knowledge Base:
119591 How to obtain Microsoft support files from online services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

Update detail information


To install this update, install April 2014, update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 (2919355) in Windows 8.1 or Windows Server 2012 R2.

Registry information

To apply this update, you don't have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this update.

Update replacement information

This update doesn't replace a previously released update.


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


Learn about the terminology that Microsoft uses to describe software updates.

File Information

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). Be aware that dates and times for these files on your local computer are displayed in your local time and with your current daylight saving time bias. The dates and times may also change when you perform certain operations on the files.