Optimizing for Static Workloads

The following table describes workload optimization parameters and their settings.

Parameter	Settings	Impact
Set Object Cache Time to Live (TTL) appropriately. Default: 30 seconds	Using Regedt32, navigate to HKEY_LOCAL_MACHINE\ System\ CurrentControlSet\ Services\ InetInfo\ Parameters. Add the value ObjectCacheTTL if it's not already there. Set to the desired value. If you do not know how long you want IIS to keep an unused file open, leave ObjectCacheTTL at its default value.	This changes the frequency with which the cache scavenger runs. If your content fits in memory and is largely static, you can even disable the scavenger by setting it to 0xffffffff. A high ObjectCacheTTL works best for sites with a small number of "popular" files. If the number of frequently requested files is large, a high ObjectCacheTTL may not help. Setting this entry high tells IIS to try to keep unused files open longer. This is useful if you expect these files to be reused within the TTL period. If you do not expect the files to be reused often, or the system appears low on resources, use a lower ObjectCacheTTL to conserve resources. You can also use OpenFilesInCache to limit the number of files IIS will keep open.
Set OpenFilesInCache to a value large enough to cache all the open handles. Default: 1000 for every 32 MB of physical memory	Using Regedt32, navigate to HKEY_LOCAL_MACHINE\ System\ CurrentControlSet\ Services\ InetInfo\ Parameters. Add the value OpenFilesInCache if it's not already there. Set to the desired value. The value will depend on the amount of memory you want to make available for the IIS cache, and the number of file handles you want cached.	Large Web sites will need to keep more file handles open for maximum performance. If the content on your site is static, you can greatly increase the performance of your Web server by maximizing the number of files served from RAM instead of from disk. You can monitor the number of cached file handles using the Cached File Handles counter under Internet Information Service Global in the Windows NT Performance Monitor.

Parameter

Settings

Impact

Set Object Cache Time to Live (TTL) appropriately.

Default: 30 seconds

Using Regedt32, navigate to HKEY_LOCAL_MACHINE\
System\
CurrentControlSet\
Services\
InetInfo\
Parameters.

Add the value ObjectCacheTTL if it's not already there.

Set to the desired value. If you do not know how long you want IIS to keep an unused file open, leave ObjectCacheTTL at its default value.

This changes the frequency with which the cache scavenger runs. If your content fits in memory and is largely static, you can even disable the scavenger by setting it to 0xffffffff.

A high ObjectCacheTTL works best for sites with a small number of "popular" files. If the number of frequently requested files is large, a high ObjectCacheTTL may not help. Setting this entry high tells IIS to try to keep unused files open longer. This is useful if you expect these files to be reused within the TTL period. If you do not expect the files to be reused often, or the system appears low on resources, use a lower ObjectCacheTTL to conserve resources. You can also use OpenFilesInCache to limit the number of files IIS will keep open.

Set OpenFilesInCache to a value large enough to cache all the open handles.

Default: 1000 for every 32 MB of physical memory

Using Regedt32, navigate to HKEY_LOCAL_MACHINE\
System\
CurrentControlSet\
Services\
InetInfo\
Parameters.

Add the value OpenFilesInCache if it's not already there.

Set to the desired value. The value will depend on the amount of memory you want to make available for the IIS cache, and the number of file handles you want cached.

Large Web sites will need to keep more file handles open for maximum performance. If the content on your site is static, you can greatly increase the performance of your Web server by maximizing the number of files served from RAM instead of from disk. You can monitor the number of cached file handles using the Cached File Handles counter under Internet Information Service Global in the Windows NT Performance Monitor.