Static gzip compression with IIS 7 when using mod_jk

0
votes

I have a web application running on JBoss and I am using IIS 7 for load balancing JBoss instances. Static files (ex: CSS, JS) are served from IIS. I am using mod_jk ISAPI filter to bridge IIS and JBoss.

I have enabled static compression in IIS. However, the CSS files served from IIS were not getting gzip compressed (I have checked this by examining the response header and it doesnt have content-encoding: gzip header).

Post this, I enabled dynamic compression in IIS and then the CSS files were compressed with gzip. I checked my uriworkermap.properties file and it is not routing CSS file request to JBoss. I am puzzled as to why IIS wouldnt compress CSS files with static compression enabled and only compresses when dynamic compression is enabled.

Thanks, Kishor

1
iis-7gzipiis-7.5mod-jk

1 Answers

1
votes

This is probably a result of IIS deciding not to compress the content as it's not considered "frequently hit". If you request the file twice within 10 seconds (make sure you're not hitting a cache, ctrl-F5), does it then compress it?

If so, setting the frequentHitThreshold attribute to 1 on the system.webServer/serverRuntime node in the applicationHost.config file should do the trick, as documented at http://www.iis.net/ConfigReference/system.webServer/serverRuntime.

You can do this by executing the following command as an administrator:

%windir%\system32\inetsrv\appcmd set config /section:serverRuntime /frequentHitThreshold:1 /commit:apphost

A word of warning - the "frequent hit" concept does not seem specific to compression. I have no idea whether there are other consequences as a result of setting this!