FIX: Slow performance when you request access to files in an IIS 7.5 virtual directory that points to a UNC share

Applies to: Internet Information Services 7.5

Symptoms


Consider the following scenario:
  • You create a virtual directory that points to a Universal Naming Convention (UNC) path of a shared folder share on Internet Information Services (IIS) 7.5.
  • You enable the Output Caching feature in IIS 7.5.
  • You have files in the shared folder. The sizes of the files are larger than the Maximum cached response size limit of the Output Caching feature.
  • The server that is running IIS 7.5 receives a request that requests access to the files.
In this scenario, the server takes more time to send a response than expected.

Note This issue does not occur in Internet Information Services (IIS) 6.0.

Cause


This issue occurs because of an error in the static file handler.

When this error occurs, the static file handler incorrectly registers an FCN handler to monitor the UNC share even when FCNs are disabled on the computer. Therefore, many FCNs have to be processed if many UNC-share files are changed, and the issue that is mentioned in the "Symptoms" section occurs.

Note To disable FCNs on the computer, set the following registry entry to the binary value of 0:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\InetInfo\Parameters\DoDirMonitoringForUNC

Resolution


Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that 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 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 hotfix, you must be running one of the following operating systems:
  • Windows 7
  • Windows 7 Service Pack 1 (SP1)
  • Windows Server 2008 R2
  • Windows Server 2008 R2 Service Pack 1 (SP1)

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix has the file attributes (or later file attributes) 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 item in Control Panel.

For all supported x86-based versions of Windows 7
File nameFile versionFile sizeDateTimePlatform
Static.dll7.5.7600.2097538,40028-May-201104:41x86
Static.dll7.5.7601.2173538,40028-May-201105:58x86

For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Static.dll7.5.7600.2097540,96028-May-201105:28x64
Static.dll7.5.7601.2173540,96028-May-201105:18x64
Static.dll7.5.7600.2097538,40028-May-201104:41x86
Static.dll7.5.7601.2173538,40028-May-201105:58x86

For all supported IA-64based versions of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Static.dll7.5.7600.2097599,84028-May-201104:22IA-64
Static.dll7.5.7601.2173599,84028-May-201104:08IA-64
Static.dll7.5.7600.2097538,40028-May-201104:41x86
Static.dll7.5.7601.2173538,40028-May-201105:58x86



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 output caching in IIS 7, visit the following Microsoft website:
For more information about how to debug and tune the HTTP.SYS output cache for IIS 7.5 in Windows Server 2008 R2 , visit the following Microsoft website:

Additional file information

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7
File nameUpdate.mum
File versionNot Applicable
File size2,684
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameX86_27bc706a6bae5115d3a02a0bde039511_31bf3856ad364e35_6.1.7601.21735_none_41616fc28c356691.manifest
File versionNot Applicable
File size713
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameX86_747c31208e092fb1535fe371584b1432_31bf3856ad364e35_6.1.7600.20975_none_cca9167336313052.manifest
File versionNot Applicable
File size713
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameX86_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7600.20975_none_7682b45693f74b35.manifest
File versionNot Applicable
File size3,311
Date (UTC)28-May-2011
Time (UTC)05:13
PlatformNot Applicable
File nameX86_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7601.21735_none_7894510c90fd475d.manifest
File versionNot Applicable
File size3,311
Date (UTC)28-May-2011
Time (UTC)06:27
PlatformNot Applicable
Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
File nameAmd64_72be0542b75202ba927d85573da2e852_31bf3856ad364e35_6.1.7600.20975_none_533b87653b17dd01.manifest
File versionNot Applicable
File size1,076
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameAmd64_7e216c05f8db4c816164485f1361ea9c_31bf3856ad364e35_6.1.7601.21735_none_9422c16919a3a680.manifest
File versionNot Applicable
File size1,076
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameAmd64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7600.20975_none_d2a14fda4c54bc6b.manifest
File versionNot Applicable
File size3,317
Date (UTC)28-May-2011
Time (UTC)06:11
PlatformNot Applicable
File nameAmd64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7601.21735_none_d4b2ec90495ab893.manifest
File versionNot Applicable
File size3,317
Date (UTC)28-May-2011
Time (UTC)07:08
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size3,120
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameWow64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7600.20975_none_dcf5fa2c80b57e66.manifest
File versionNot Applicable
File size2,992
Date (UTC)28-May-2011
Time (UTC)04:57
PlatformNot Applicable
File nameWow64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7601.21735_none_df0796e27dbb7a8e.manifest
File versionNot Applicable
File size2,992
Date (UTC)28-May-2011
Time (UTC)06:12
PlatformNot Applicable


Additional files for all supported IA-64based versions of Windows Server 2008 R2
File nameIa64_7eeab49eb3cfa504e4fabc3ced786ef8_31bf3856ad364e35_6.1.7601.21735_none_aa547ad83786fa54.manifest
File versionNot Applicable
File size1,074
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameIa64_a8040d39da5602ae0f8ced6054284cd7_31bf3856ad364e35_6.1.7600.20975_none_ab09b85474e48880.manifest
File versionNot Applicable
File size1,074
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameIa64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7600.20975_none_7684584c93f55431.manifest
File versionNot Applicable
File size3,314
Date (UTC)28-May-2011
Time (UTC)06:06
PlatformNot Applicable
File nameIa64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7601.21735_none_7895f50290fb5059.manifest
File versionNot Applicable
File size3,314
Date (UTC)28-May-2011
Time (UTC)07:02
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size2,347
Date (UTC)31-May-2011
Time (UTC)18:59
PlatformNot Applicable
File nameWow64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7600.20975_none_dcf5fa2c80b57e66.manifest
File versionNot Applicable
File size2,992
Date (UTC)28-May-2011
Time (UTC)04:57
PlatformNot Applicable
File nameWow64_microsoft-windows-i..aticcontentbinaries_31bf3856ad364e35_6.1.7601.21735_none_df0796e27dbb7a8e.manifest
File versionNot Applicable
File size2,992
Date (UTC)28-May-2011
Time (UTC)06:12
PlatformNot Applicable