The throughput of an Application Request Routing server decreases when you enable the disk cache feature on ARR for IIS 7.0 or for IIS 7.5

Consider the following scenario:

• You install the Microsoft Application Request Routing (ARR) 2.0 or the ARR 2.1 module on a computer that is running Internet Information Services (IIS) 7.0 or IIS 7.5.
• You enable the disk cache feature for ARR.

In this scenario, the throughput of this ARR server decreases periodically. The intervals between each decrease in throughput are two times as long as the cache cleanup interval value that is configured in ARR.

For example, if the cache clean-up interval value is set to 5 minutes, the issue will be seen in 10 minute intervals.

Note This issue usually occurs on servers that experience a high volume of traffic. For example, the servers are used to transfer smooth video streaming.

The decrease in throughput occurs because the ARR module performs a file handle cleanup when the disk cache feature is enabled. Locking that occurs during this operation interferes with the overall performance of ARR.

Update information

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

Download the AMD64 package now. (http://www.microsoft.com/downloads/en/details.aspx?FamilyID=975291af-0831-4064-970e-b11d288b10ed)

Download the x86 package now. (http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9b394e6c-2cf2-46d6-b75d-4cb44586de7f)

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base: 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.

Prerequisites

To apply this update, you must have the ARR 2.0 or ARR 2.1 module for Internet Information Services (IIS) 7.0 or for IIS 7.5 installed.

Restart requirement

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

Update replacement information

This update does not replace any other update.

File Information

The English version of this update 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 ARR for IIS 7.0 or for IIS 7.5

For all supported x64-based versions of ARR for IIS 7.0 or for IIS 7.5

To work around this issue, increase the cache cleanup interval value.

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

To download the x86-based version of the ARR 2.0 module for IIS 7.0 or for IIS 7.5, visit the following Microsoft website:
To download the x64-based version of the ARR 2.0 module for IIS 7.0 or for IIS 7.5, visit the following Microsoft website:For more information about the ARR proxy settings, visit the following Microsoft website:For more information about cache configuration for ARR, visit the following Microsoft website:For more information about the ARR module, visit the following Microsoft website:For more information about performance counters for ASP.NET, visit the following Microsoft website: