Considering the following scenario:
- You have a Windows Server 2012 failover cluster that is configured by using continuously available file shares.
- An
I/O stress test is running on a Windows 8 or Windows Server 2012-based
client against the failover cluster. The stress test has a high ratio of
open and close operations to data operations. For example, the test
repeatedly opens a file on the file share, reads the file, and then
closes the file.
Note This scenario may be found in stress tests but does not map directly to customer-usage scenarios.
In
this scenario, you may experience I/O errors during failover.
Additionally, the following event may be logged in the System log:
Event ID: 50
Event Source: Mup
Description:
{Delayed Write Failed} Windows was unable to save all the data from the
file <file name>.The data has been lost. This error may be caused
by a failure of your computer hardware or network connection. Please
try to save this file elsewhere.
When
a file on the file share is opened, a file handle is created. After the
file is closed, the Server Message Block (SMB) redirector will cache
the file handle for a short time. However, there is a limit on the
number of handles that can be cached in this manner. During the stress
test, the SMB scavenger can fall behind in closing the cached handles.
This may result in a large backlog of handles. Eventually, the number of
handles exceeds the limit that can be failed over within the continuous
availability time-out and some I/O operations may fail. By default, the
continuous availability time-out is 60 seconds.
This hotfix is also available at
Microsoft Update Catalog.
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 Web site:
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 8 or Windows Server 2012.
Restart requirement
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace a previously released hotfix.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
You can use the following Windows PowerShell command to obtain the number of handles on the SMB client:
When
the issue occurs, the number of handles is much more than expected. For
example, you may see more than 10,000 handles although the expected
number is about 100 handles.
Hardware configuration and performance may affect the threshold at which the issue occurs.
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
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