Data loss occurs when a Windows Server 2012-based computer that has the data deduplication feature enabled crashes

Symptoms

Assume that you have a Windows Server 2012-based computer that has the data deduplication feature enabled on some volumes. When the computer crashes, data loss occurs unexpectedly. 

Cause

This issue occurs because a reparse point is set before all the deduplication data recalls are completed. The data deduplication feature recalls a section of a file to write to by using a writing process. Then, the feature flushes the written data from the recalled section to a reparse point. However, when lots of writing processes are running at the same time, the flush may be performed before all the recalls are completed. Therefore, when the computer crashes, the data that was written to the unflushed recalls is lost.

Resolution

To resolve this issue, install update rollup 2889784, or install the hotfix that is described in this article.

Update information

For more information about how to obtain update rollup 2889784, click the following article number to view the article in the Microsoft Knowledge Base:

2889784 Windows RT, Windows 8, and Windows Server 2012 update rollup: November 2013

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:

http://support.microsoft.com/contactus/?ws=supportNote 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.

PrerequisitesTo apply this hotfix, you must be running Windows Server 2012.

Registry informationTo use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirementYou must restart the computer after you apply this hotfix.

Hotfix replacement informationThis 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 2012 file information notesImportant Windows 8 hotfixes and Windows Server 2012 hotfixes are included in the same packages. However, only "Windows 8" 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 8" 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

    6.2.920 0.16 xxx

    Windows Server 2012

    RTM

    GDR

    6.2.920 0.20 xxx

    Windows Server 2012

    RTM

    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) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2012" 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 2012

File name

File version

File size

Date

Time

Platform

Dedup.sys

6.2.9200.16731

419,672

05-Oct-2013

06:37

x64

Dedup.sys

6.2.9200.20842

419,672

07-Oct-2013

01:01

x64




Status

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

More Information

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 for Windows Server 2012

Additional files for all supported x64-based versions of Windows Server 2012

File property

Value

File name

Amd64_2ecbc148ca47d3bfdc3f487e5afc5711_31bf3856ad364e35_6.2.9200.20843_none_5bca5174765562d8.manifest

File version

Not applicable

File size

704

Date (UTC)

07-Oct-2013

Time (UTC)

19:01

Platform

Not applicable

File name

Amd64_785429e2874fcd5497dc98668a4ece4c_31bf3856ad364e35_6.2.9200.16731_none_15de0325fe8f0190.manifest

File version

Not applicable

File size

704

Date (UTC)

07-Oct-2013

Time (UTC)

19:01

Platform

Not applicable

File name

Amd64_microsoft-windows-dedup-filter_31bf3856ad364e35_6.2.9200.16731_none_610e504ee1564f28.manifest

File version

Not applicable

File size

7,824

Date (UTC)

05-Oct-2013

Time (UTC)

06:48

Platform

Not applicable

File name

Amd64_microsoft-windows-dedup-filter_31bf3856ad364e35_6.2.9200.20843_none_618f1dc1fa7a3d91.manifest

File version

Not applicable

File size

7,824

Date (UTC)

07-Oct-2013

Time (UTC)

02:14

Platform

Not applicable

File name

Package_1_for_kb2897097_bf~31bf3856ad364e35~amd64~~6.2.1.0.mum

File version

Not applicable

File size

1,769

Date (UTC)

07-Oct-2013

Time (UTC)

19:01

Platform

Not applicable

File name

Package_1_for_kb2897097~31bf3856ad364e35~amd64~~6.2.1.0.mum

File version

Not applicable

File size

2,480

Date (UTC)

07-Oct-2013

Time (UTC)

19:01

Platform

Not applicable

File name

Package_for_kb2897097_rtm_bf~31bf3856ad364e35~amd64~~6.2.1.0.mum

File version

Not applicable

File size

1,426

Date (UTC)

07-Oct-2013

Time (UTC)

19:01

Platform

Not applicable

File name

Package_for_kb2897097_rtm~31bf3856ad364e35~amd64~~6.2.1.0.mum

File version

Not applicable

File size

1,445

Date (UTC)

07-Oct-2013

Time (UTC)

19:01

Platform

Not applicable

File name

Update-bf.mum

File version

Not applicable

File size

1,558

Date (UTC)

07-Oct-2013

Time (UTC)

19:01

Platform

Not applicable


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