This article was previously published under Q188352
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ASP caching in low memory situations may cause "Server Too Busy" errorsand/or blank pages returned to client browsers. Memory usage by theInetinfo process will be very high.
This problem occurs because too much data is being cached and the defaultnumber of ASP files to cache is set to unlimited in Internet InformationServer (IIS) 4.0. ASP attempts to cache ASP files until the process runsout of virtual memory. The IIS computer stops processing pages and returnsthe "Server Too Busy" error or blank pages to client browsers.
Note that there are other causes of the "Server Too Busy" errors.
Windows NT Server or Workstation 4.0
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to:
152734 how to obtain the latest windows nt 4.0 service pack
For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:
To resolve this problem, obtain the latest service pack for Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows NT Server version 4.0, Terminal Server Edition Service Pack 6.
ASP has been modified to flush the cache when it receives an "Out ofMemory" error. This enables it to recover gracefully. Please see thefollowing paragraphs for information on how to do additional tuning of theASP cache, so that it does not flush the ASP cache frequently, thusnullifying the benefits of caching.
Tune the AspScriptFileCacheSize (the number of ASP files to cache)settings for IIS. This setting is documented in IIS Help. The settingsdepend on a number of factors, including the amount of data in the server-side Include files and the number of ASP files that are cached. It isreasonable to start with a number like 250, and then monitor the ASP cachehit ratio using Performance Monitor. If it is below 90 percent, then raisethe number. If it is above 90 percent, then any changes to the Web's pagescan and will most likely change the tuning parameters.To change the ASP process options, do the following:
Open the IIS MMC.
Right-click on the computer name for the IIS computer.
Edit the master properties for the WWW Service.
Click the Home Directory tab.
Click the Configuration button.
Click the Process Options tab.
Modify the settings in the Script File Cache group.
NTDLL may not efficiently use the virtual address space, whichcauses the processes to run out of memory sooner. Apply the fix listed inthe following article in the Microsoft Knowledge Base:
216383 MemoryAllocations May Fail When There Are Large Free Blocks
Some improvement can be made by increasing the per-process addressspace from 2 GB to 3 GB. For additional information, please see thefollowingarticle in the Microsoft Knowledge Base:
171793 Informationon Application Use of 4GT RAM Tuning
Note that more physical RAM may be required to reduce possible pagingafter this change is made.Redesign the Web application.Disable ASP caching.