IIS 6 HTTP Compression

Question

I was doing some looking the other day via fiddler. ( a tool which i know very little about) We have been having some performance issues here with an old classic asp app in addition to even recent changes which have been done in asp.net.

I remember hearing about HTTP compression and making sure that that is turned on in IIS. The site is being hosted on a w2k3 box running IIS6 i believe. I followed the following article to make sure that it was setup correctly: http://weblogs.asp.net/owscott/IIS-Compression-in-IIS6.0

how i am checking to see if compression is working is via fiddler as i mention. I am simply clicking on the item in question within fiddler and clicking on transformer and looking to see if the gzip or defalte encoding are selected. They never are and no compression seems to always be selected.

My question is how do i go about getting http compression setup correctly and how do i verify that it is working properly?

Last, does someone know of a good resource to get an overview of how to analyze a page/site via fiddler? I don't understand what the highlighting is for example and would like a quick references as to what to focus on and where within the tool to make sure the site is running optimally.

Thanks for the assistance.

Answer 1

First of all: I never used "3rd party tool" for enable compression on IIS 6 -- native/buildin tools more than enought.

OPTIONALLY 1. Create IIS Temporary Compressed Files folder 2. Add IIS_WPG user with write permission and IUSR with read permission

1. In IIS, on web site propertie, tab "Service" enabled "Compress application files" and "Compress static files"
2. Make sure option "Enable Direct Metabase edit" enabled for your IIS 6.0
3. In "MetaBase.xml" following section should be like this (pay attention on added file extension, following sample for classic ASP):

 <IIsCompressionScheme Location ="/LM/W3SVC/Filters/Compression/deflate" HcCompressionDll="%windir%\\system32\\inetsrv\\gzip.dll" HcCreateFlags="0" HcDoDynamicCompression="TRUE" HcDoOnDemandCompression="TRUE" HcDoStaticCompression="TRUE" HcDynamicCompressionLevel="10" HcFileExtensions="css txt gif png js htm html" HcOnDemandCompLevel="10" HcPriority="1" HcScriptFileExtensions="asp dll exe" > </IIsCompressionScheme> <IIsCompressionScheme Location ="/LM/W3SVC/Filters/Compression/gzip" HcCompressionDll="%windir%\\system32\\inetsrv\\gzip.dll" HcCreateFlags="1" HcDoDynamicCompression="TRUE" HcDoOnDemandCompression="TRUE" HcDoStaticCompression="TRUE" HcDynamicCompressionLevel="10" HcFileExtensions="css txt gif png js htm html" HcOnDemandCompLevel="10" HcPriority="1" HcScriptFileExtensions="asp dll exe" > </IIsCompressionScheme> 

NOTE: Before make changes in "MetaBase.xml" you should stop IIS.

1. Open http://checkgzipcompression.com and make test for your web site/page.

Results for http://www.1click.lv/default.asp YES, it's GZIP enabled!

Uncompressed size: 9,531 bytes Compressed size: 2,867 bytes

By compressing this page with GZIP, 69.9% bandwidth was saved. Technical details:

HTTP result: 200 Content type: text/html Compression time for 9,531 bytes: 1 millisecond Execution time of HTTP request: 194 milliseconds Webserver name: Microsoft-IIS/6.0