Article ID: 840390 - View products that this article applies to.
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Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/256986/ )Description of the Microsoft Windows Registry
This article discusses a software update that changes the current behavior of the Server Message Block (SMB) protocol SMB_COM_FLUSH command in Microsoft Windows Server 2003. This software update can help improve file server performance.
In certain hardware configurations, the throughput of a Microsoft Windows Server 2003-based file server may be limited by disk write performance. Typically, these configurations use a single disk spindle on the server, and clients issue many writes to the server. You may want to consider using this software update to increase file server performance if both of the following conditions are true:
The SMB_COM_FLUSH command makes sure that all data and allocation information for the corresponding file has been written to stable storage. A response is not sent to the client until the writes are complete. However, two factors may contribute to unnecessarily poor server performance:
Software update informationA supported feature that modifies the default behavior of the product is available from Microsoft. However, this feature is intended to modify only the behavior that this article describes. Apply this feature only to systems that specifically require it. This feature might receive additional testing. Therefore, if the system is not severely affected by the lack of this feature, we recommend that you wait for the next software update that contains this feature.
If the feature 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 feature.
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 feature. 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:
http://support.microsoft.com/contactus/?ws=supportNote The "Hotfix download available" form displays the languages for which the feature is available. If you do not see your language, it is because the feature is not available for that language.
PrerequisitesNo prerequisites are required.
Restart requirementYou must restart your computer after you apply this software update.
Software update replacement informationThis software update does not replace any other software updates.
File informationThe English version of this software update has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
Date Time Version Size File name Platform ------------------------------------------------------------------- 15-Apr-2004 23:13 5.2.3790.163 355,328 Srv.sys x86 15-Apr-2004 23:12 5.2.3790.163 991,744 Srv.sys IA-64
When to apply this software updateMicrosoft recommends that you consider using this software update only when all the following conditions are true:
How to configure this software updateAfter you apply this software update, you must add and configure the TreatHostAsStableStorage registry entry in the following subkey:
To change to the new behavior of the SMB_COM_FLUSH command, you must set the value of the TreatHostAsStableStorage entry to a non-zero value. If the value is set to zero, or if the value does not exist, the behavior of the SMB_COM_FLUSH command does not change from its original default behavior.
To add and to configure the TreatHostAsStableStorage registry entry, follow these steps.Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
The SMB_COM_FLUSH command is a part of the Common Internet File System (CIFS) protocol. To download the CIFS protocol, visit the following Microsoft Web site:
http://www.microsoft.com/downloads/details.aspx?FamilyID=c4adb584-7ff0-4acf-bd91-5f7708adb23c&displaylang=enFor additional information about Microsoft software updates, click the following article number to view the article in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/824684/ )Description of the standard terminology that is used to describe Microsoft software updates
Article ID: 840390 - Last Review: January 10, 2015 - Revision: 3.0