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FosterPatch_243's avatar
FosterPatch_243
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Jan 15, 2016

Troubleshooting Dynamic Ratio Load Balancing

Hello,

 

I have a collection of 8 servers that need balancing, and unfortunately all other balancing methods have proven ineffective, due to the spontaneous nature of the spikes they receive. This has made me conclude that Dynamic Ratio is the only way to go. The servers are currently using IIS 8.5 and Windows 2012 R2.

 

The following steps are what I took in my attempt to get this working.

 

-Created C:\Inetpub\scripts, place web.config in there with the following text:

 

-Created C:\Inetpub\scripts\bin and placed F5.IsHandler.dll inside.

 

-Used Command Prompt to enter, "appcmd set config "Default Web Site/scripts" /section:anonymousAuthentication /overrideMode:Allow /commit:APPHOST"

 

-Went to IIS Manager, created a new Application Pool titled "F5 Application Pool", set its identity to NetworkService

 

-Created a new application called "scripts", set the physical path to the bin folder.

 

-Modified the "Authentication" of scripts to disabled on everything except Basic Authentication

 

-Went to Monitors on Traffic Manager, created a new monitor named "WMI_Monitor_F5", used default settings and changed the URL to the correct directory.

 

-Went to each server on a node level, changed "Health Monitors" from Node Default to Node Specific, added WMI_Monitor_F5 to each.

 

-Changed the Load Balancing Method on the pool level to Dynamic Ratio.

 

Everything seemed to work, however, when attempting to use curl to verify, it failed, showing that something went wrong.

 

Does anyone know if I missed something, or have made a mistake somewhere? Any help would be greatly appreciated, thank you.

 

6 Replies

  • It's very clear my web.config was not posted correctly, you can view that here: http://pastebin.com/fCtvvUg1
  • What is the status of the virtual server? If the virtual is offline then the curl command is expected to fail. (tmsh show ltm virtual)

     

    You seem to have the steps correct, can you confirm that you followed this guide? If so, SOL13853 will help you to debug the WMI monitor.

     

    PS: The guide only states compatibility up to IIS 7.0.

     

  • Hello again,

     

    It is to my belief the issue comes down to the dll file, F5.IsHandler.dll. The most recent documentation for use of this dll is IIS 7.5, and we are using 8.5. Is there any updated dll files available for use?

     

    I have come to this conclusion because I was able to successfully connect using curl, and everything seems to work fine, yet it is still returning "invalid data"

     

    Thanks

     

    • Danny_Epperson_'s avatar
      Danny_Epperson_
      Historic F5 Account
      I would agree. Microsoft mentions deprecating WMI, perhaps this is related. If you haven't already looked into it, try the IIS 6 WMI Compatibility feature. http://www.iis.net/learn/install/installing-iis-85/installing-iis-85-on-windows-server-2012-r2
    • FosterPatch_243's avatar
      FosterPatch_243
      Icon for Nimbostratus rankNimbostratus
      I attempted adding the IIS 6 WMI compatibility feature to the servers... No change. IIS 8.5 is about 3 years old now...How does F5 not have standard procedures for it? If I am attempting to use f5isapi.dll and this IIS 6 compatibility feature, should I change the web.config as well?
    • FosterPatch_243's avatar
      FosterPatch_243
      Icon for Nimbostratus rankNimbostratus
      I created a domain account name, then added the account to every affected server, and made sure that is the username/password in big-ip, and also in IIS Manager. Still returning "invalid data"... I really don't know what else to do. I've tried with F5.IsHandler, f5isapi, and f5isapi64