HTTP compression settings for Internet Information Services (IIS)

The <httpCompression> element specifies the HTTP compression settings for Internet Information Services (IIS) 7. HTTP compression can provide faster transmission times between IIS and client browsers that can accept compressed files.

Note: An HTTP client must initiate communication for compressed content by sending the appropriate HTTP Accept-encoding header. If a client is not capable of HTTP compression, it will not pass that header and IIS 7 will always return uncompressed content.

There are two different types of compression that IIS 7 uses:

· Static Compression:

IIS 7 caches compressed static content in the path that is specified by the directory attribute, which increases compression performance by eliminating the need to recompress content that has already been compressed. After IIS 7 has compressed a file, subsequent requests are given the compressed copy of the file from the cache directory.

The staticCompressionEnableCpuUsage and staticCompressionDisableCpuUsage attributes specify when IIS 7 will compress static files based on CPU usage.

You should use static compression with files that do not typically change, such as HTML files (*.html, *.htm), text files (*.txt), Microsoft Office documents (*.doc, *.xls, *.ppt), etc. The size of these files can be reduced through compression, which reduces download times for client requests and reduces bandwidth on the server.

Note: Image files such as *.jpg and *.png files are also static files, but typically they do not benefit from HTTP compression because these image files are already compressed.

· Dynamic Compression:

Unlike static compression, IIS 7 performs dynamic compression each time a client requests the content, but the compressed version is not cached to disk. This change is made because of the primary difference between static and dynamic content. Static content does not change. However, dynamic content is typically content that is created by an application and therefore changes often, such as Active Server Pages (ASP) or ASP.NET content. Since dynamic content should change often, IIS 7 does not cache it.

The dynamicCompressionEnableCpuUsage and dynamicCompressionDisableCpuUsage attributes specify when IIS 7 will compress dynamic files based on CPU usage.

WINDOWS SERVER 2012 OR WINDOWS SERVER 2012 R2

On the taskbar, click Server Manager.

In Server Manager, click the Manage menu, and then click Add Roles and Features.

In the Add Roles and Features wizard, click Next. Select the installation type and click Next. Select the destination server and click Next.

On the Server Roles page, expand Web Server (IIS), expand Web Server, expand Performance, and then select Static Content Compression and/or Dynamic Content Compression. Click Next.

On the Select features page, click Next.

On the Confirm installation selections page, click Install.

On the Results page, click Close.