Microsoft KB Archive/253146

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Article ID: 253146

Article Last Modified on 11/21/2006


  • Microsoft Internet Information Services 5.0

This article was previously published under Q253146


This article provides some generic information about possible performance-enhancement settings that may be helpful to tune Internet Information Server (IIS) 5.0. The default settings for Internet Information Services 5.0 are adequate for most uses. When you host sites serving a large number of users, tuning the parameters listed in the "More Information" section of this article may help to increase performance. All changes should be verified on a test computer before you make changes to a production computer.



The AspProcessorThreadMax metabase property specifies the maximum number of worker threads per processor that IIS creates. The setting can dramatically influence the scalability of your Web applications and the performance of your server in general. Because it defines the maximum number of ASP requests that can run simultaneously, this setting should remain at the default unless your ASP applications are making long-running calls to external components. By default, AspProcessorThreadMax is set to 25.


The AspRequestQueueMax metabase property specifies the maximum number of concurrent ASP requests that are permitted into the queue. Any client browsers attempting to request ASP files when the queue is full are given an HTTP 500 "Server too busy" error message. By default, AspRequestQueueMax is set to 3000.


IIS places all ASP requests into a queue. If the request has been queued for longer than the number of seconds specified by the AspQueueConnectionTestTime metabase property, ASP checks to determine whether the client is still connected before it executes the request. If the client is no longer connected, the request is not processed and is deleted from the queue. You can use the AspQueueConnectionTestTime metabase property to make sure that IIS does not waste time processing a request that has been abandoned by the user. By default, AspQueueConnectionTestTime is set to 3.


The AspScriptEngineCacheMax property specifies the maximum number of scripting engines that ASP pages will keep cached in memory. By default, AspScriptEngineCacheMax is set to 125.


The AspSessionTimeOut property specifies the default amount of time (in minutes) that a session object is maintained after the last request associated with the object is made. AspSessionTimeOut can be used to tune your ASP applications. Because session objects consume some memory resources, limiting the lifetime of an individual session with this property makes your applications more scalable. By default, AspSessionTimeOut is set to 20.

WARNING: Modifying the metabase incorrectly can cause serious problems that may require you to reinstall IIS 5.0. Microsoft cannot guarantee that problems resulting from incorrectly modifying the metabase can be resolved. Modify the metabase at your own risk.

Run the Adsutil.vbs utility from the <%SYSTEMDRIVE%>\inetpub\adminScripts directory. For example, to reconfigure the AspRequestQueueMax metabase property, type the following command:

adsutil.vbs set w3svc/AspRequestQueueMax <NewValue>

Where <NewValue> is the number of requests that ASP should use per processor.

Note: For all entries, these settings change the value at the Master WWW Properties level, where they are inherited by all new Web applications and all existing applications that have not explicitly set a different value.


For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:

300672 HOW TO: Create a Metabase Backup in IIS 5

238583 How to Tune the ASPProcessorThreadMax

233477 PRB: Session.Timeout Has a Max of 24 Hours

Keywords: kbinfo KB253146